SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES ? NUMBER 19
Mineral Sciences Investigations
1974-1975
Brian Mason
EDITOR
ISSUED
MAR 9
SMITHSONIAN INSTITUTION PRESS
City of Washington
1977
ABSTRACT
Mason, Brian, editor. Mineral Sciences Investigations 1974-1975. Smithsonian
Contributions to the Earth Sciences, number 19, 125 pages, 48 figures, 37 tables,
1977.?Nine short contributions from the Smithsonian's Department of Mineral
Sciences for 1974 and 1975 are gathered together in this volume. These contri-
butions comprise an account of the composition of garnet xenocrysts from three
kimberlite pipes in Arizona and New Mexico; a catalog of major element chem-
istry of abyssal volcanic glasses, and the application of these data to determine
magma compositions; descriptions of the Harleton (Texas), St. Mary's County
(Maryland), and Ras Tanura (Saudi Arabia) chondritic meteorites; a compara-
tive study of eight chondrite meteorites from India and Pakistan; geochemical
data on separated components of the Allende carbonaceous chondrite; and a
mineralogical and chemical study of silicate inclusions in the El Taco mass of
the Campo del Cielo iron meteorite.
OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recordedin the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: Aerial view of
Ulawun Volcano, New Britain.
Library of Congress Cataloging in Publication DataMain entry under title:
Mineral sciences investigations, 1974-1975.(Smithsonian contributions to the earth sciences ; no. 19)
"Nine short contributions from the Smithsonian's Department of Mineral Sciences."Includes bibliographies.
Supt. of Docs, no.: SI 1.26:191. Meteorites?Addresses, essays, lectures. 2. Petrology?Addresses, essays, lectures. 3. Min-
eralogy?Addresses, essays, lectures. I. Mason, Brian Harold, 1917- II. National Museumof Natural History. Dept. of Mineral Sciences. III. Series: Smithsonian Institution. Smith-
sonian contributions to the earth sciences ; no. 19.QE1.S227 no. 19 [QE395] 550' .8s [549' .1] 76-608124
Contents
PageMINERALOGY
COMPOSITION OF GARNET XENOCRYSTS FROM THREE KIMBERLITE PIPES IN
ARIZONA AND NEW MEXICO, by George S. Switzer 1
PETROLOGY
ABYSSAL BASALTIC GLASSES AS INDICATORS OF MAGMA COMPOSITIONS, by
Gary R. Byerly, William G. Melson, Joseph A. Nelen, and Eugene
Jarosewich 22
A CATALOG OF THE MAJOR ELEMENT CHEMISTRY OF ABYSSAL VOLCANIC
GLASSES, by William G. Melson, Gary R. Byerly, Joseph A. Nelen,
Timothy O'Hearn, Thomas L. Wright, and Tracy Vallier 31
METEORITES
THE HARLETON, TEXAS, CHONDRITE, by Roy S. Clarke, Jr., Edward P.
Henderson, and Brian Mason 61
EIGHT L-GROUP CHONDRITES: A COMPARATIVE STUDY, by Ananda Dube,
Becky J. Fredriksson, Eugene Jarosewich, Joseph A. Nelen, Albert F.
Noonan, Jane O'Keefe, and Kurt Fredriksson 71
THE RAS TANURA, SAUDI ARABIA, CHONDRITE, by Brian Mason 83
GEOCHEMICAL DIFFERENCES AMONG COMPONENTS OF THE ALLENDE ME-
TEORITE, by Brian Mason and Philip M. Martin 84
THE ST. MARY'S COUNTY, MARYLAND, CHONDRITE, by Albert F. Noonan,
Eugene Jarosewich, and Roy S. Clarke, Jr 96
MlNERALOGICAL AND CHEMICAL COMPOSITIONS OF SILICATE INCLUSIONS IN
THE EL TACO, CAMPO DEL CIELO, IRON METEORITE, by Frank Wlotzka
and Eugene Jarosewich 104
ill
Mineral Sciences Investigations
1974-1975
Composition of Garnet Xenocrysts from Three Kimberlite
Pipes in Arizona and New Mexico
George S. Siuitzer
ABSTRACT
Microprobe analyses were made of a large number
of garnet xenocrysts from three kimberlite pipes in
Arizona and New Mexico in a search for garnets
having a composition similar to those found as in-
clusions in diamond. At none of the localities were
any xenocrysts found having compositions lying
within the diamond inclusion field in Ca-Cr, Ca-
Mg-Fe, and Ca-Mg-Cr plots. From this one could
conclude that none of the three kimberlite pipes
examined is diamondiferous. If they were prospected
on the basis of garnet composition, Garnet Ridge
is the one most likely to contain diamond.
Introduction
Garnet xenocrysts in kimberlite may be derived
from three types of xenoliths: from peridotites and
eclogites of mantle origin, and disaggregated crustal
xenoliths. Consequently, garnets from any one
kimberlite pipe may vary widely in composition.
This is reflected in the wide range of colors fre-
quently seen in garnets from kimberlite. These
colors may include red, orange, yellow, violet, pur-
ple, pink, brown, with all gradations between.
George S. Switzer, Department of Mineral Sciences, National
Museum of Natural History, Smithsonian Institution, Wash'
ington, D.C. 20560.
Of particular interest are the garnets of high
pressure type considered to be of mantle origin,
and especially those having a composition similar
to garnets found as inclusions in diamond. Gurney
and Switzer (1973) have shown that there are small
compositional differences between garnets found in
common garnet peridotite xenoliths in kimberlite,
and those found as inclusions in diamond. These
differences are that the diamond inclusions have
higher magnesium and lower calcium content as-
sociated with high chromium. In their study of
garnets from the Finsch diamond mine, Gurney
and Switzer found some Mg-rich, Cr-rich, Ca-poor
garnets that fell within the composition field of
garnets previously only reported as inclusions in
diamond. These garnets are considered to have a
deeper provenance than the Mg-garnets commonly
found as xenocrysts in kimberlite and in garnet
peridotite xenoliths. Their presence in a kimberlite
should be diagnostic of the presence of diamond,
although it was not demonstrated whether or not
there was any quantitative relationship. This dis-
covery showed that N. V. Sobolev, et al. (1969) were
correct when they suggested that kimberlite heavy
mineral concentrates had not been adequately
studied to reveal their full compositional range.
An extension of the work of Gurney and Switzer
has been carried out by Lawless (1974). He found
garnets with compositions similar to those found
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 1.?Composition of ganlet inclusions in diamond used to delineate the
"diamond inclusion field"
Constituent
SiO
TiO
Al 0
fl2 3
Cr 0,2 3
V 02 3
Fe 0^2 3
FeO
MnO
MgO
CaO
Na 0
1
42.7
0.02
18.0
6.08
6.02a
0.21
23.4
1.33
97.8
2
42.6
0.02
17.9
7.09
6.93a
0.28
22.6
1.24
98.6
3
42.7
0.02
18.4
7.19
6.55a
0.28
23.3
1.09
99.5
4
41.7
0.03
17.6
7.72
7.01
0.37
22.5
1.46
98.4
5
41.4
0.08
11.1
15.9
a 6.18a
0.23
23.1
2.24
100.1
6
41.7
0.08
18.1
6.97
8.12
0.37
21.1
0.05
99.15
7
42.3
0.02
17.2
8.93
1.45
a 4.06
0.21
25.3
1.09
100.56
8
42.8
<0.01
18.2
7.9
c i.ooc
C 3.85C
0.17
25.5
1.35
100.77
9
42.5
0.05
17.3
8.77
1.47
3.72
0.19
25.1
1.77
0.02
99.03
10
42.7
0.02
18.4
5.85
C 2.76C
c 2.90C
0.18
25.1
2.46
100.37
11
40.4
0.01
10.4
17.3
5.84a
24.6
0.93
99.5
12
40.9
<0.01
16.2
9.34
6.51a
0.25
21.5
5.1
99.8
13
41.8
<0.01
16.3
8.3
0.03
2.05c
6,7C
0.34
20.7
3.2
0.05
99.5
14
40.8
0.47
18.6
4.4
0.03
5.8C
0.37
21.3
4.2
0.20
98.1
ATOMIC PROPORTIONS ON THE BASIS OF 12 OXYGENS
Si ..
Ti ..
Al ..
Cr ..
V . . .
Fe+3
Fe+2
Mn ..
Mg ..
Ca ..
Na . .
3.08 3.07
0.001 0.001
1.53 1.52
0.35 0.40
0.36 0.42
0.01 0.02
2.52 2.43
0.10 0.10
3.05 3.03
0.001 0.002
1.55 1.51
0.41 0.44
0.39 0.43
0.02 0.02
2.48 2.44
0.08 0.11
3.04
0.004
0.96
0.92
0.38
0.02
2.53
0.18
3.03 2.99
0.004 0.001
1.55 1.43
0.40 0.50
3.00
1.51
0.44
2.99 3.00
0.003 0.001
1.43 1.53
0.49 0.33
2.98 2.98 3.05
0.42u 0.081- 0.08 0.08 0.15
0.45
0.02
2.28
0.21
0.007
0.24c 0.26c 0.22c 0.17?
0.01 0.01 0.01 0.01
2.67
0.08
2.57
0.17
2.64
0.13
0.002
2.63
0.19
0.91
1.01
0.36?
2.71
0.07
1.39
0.54
0.40?
0.02
2.34
0.40
1.40
0.48
0.002
0.11C
0.41c
0.02
2.25
0.25
0.007
2.98
0.026
1.60
0.25
0.002
0.11?
0.35c
0.02
2.32
0.33
0.03
a Total iron expressed as FeO.
O i o_l_
^ Fe and Fe calculated from total iron and the structural formula by the original authors.
c FeO and Fe?0., calculated from total iron by the original authors.
Columns 1-5: From N.V. Sobolev, et al. (1969).
Column 6: From N.V. Sobolev, et al. (1971).
Columns 7-10: From Meyer and Boyd (1972).
Columns 11-12: From Meyer and Svizero (1975).
Columns 13-14: From Prinz, et al. (1975).
as inclusions in diamond in the heavy mineral con-
centrates of the Bobbejan diamond mine, Kao kim-
berlite pipe, Koffiefontein diamond mine, Newlands
kimberlite pipe, Premier diamond mine, and Sek-
retariskop kimberlite pipe. He found that diamond-
inclusion-type garnets, although rare, are more
plentiful than expected. All of the kimberlites
studied by Lawless are diamond-bearing, ranging
in diamond content from two carats per 100 metric
tons to 100 carats per 100 tons. He was unable,
however, to draw any conclusions as to whether
or not the frequency with which the diamond-
inclusion-type garnets occur is related to diamond
content of the kimberlite, because to prove this
would require the examination of an extremely
large number of garnets.
The present study is a further extension of this
work to two kimberlite occurrences in northeastern
NUMBER 19
Arizona, Garnet Ridge and Buell Park, and to
nearby Green Knobs in New Mexico. These pipes
were selected because, although extensively col-
lected at and well known for many years, no dia-
mond finds have ever been reported. They have not
been systematically prospected for diamonds, but it
seems safe to assume that they are at least very dia-
mond-poor, if not diamond-free. A specific search
was made for diamonds at Buell Park by Schmitt,
Swann, and Smith (1974:682), who report: "Ex-
haustive search through hundreds of anthills (much
to the consternation of the ants) by the authors
and other interested parties has revealed no dia-
monds."
The three kimberlite intrusions studied are
among eight scattered over a wide area in north-
eastern Arizona and nearby parts of Utah and New
Mexico. These kimberlites have been described
by many workers, including Gregory (1916, 1917);
Reagan (1927); Balk and Sun (1954); Balk (1954);
Malde (1954); Watson (1960, 1967); Malde and
Thaden (1963); O'Hara and Mercy (1966); Gavasci
and Kerr (1968); McGetchin (1968); Gavasci and
Helmstaedt (1969); Watson and Morton (1969);
McGetchin and Silver (1970); Stuart-Alexander,
Shoemaker, and Moore (1971); and Schmitt, Swann,
and Smith (1974).
Procedure
At kimberlite pipes that are being operated as
diamond mines, a garnet sample is readily obtained
from the heavy mineral concentrate from which
the diamond is extracted. To obtain a large sample
of garnet from localities such as those studied here
would normally be difficult, for the garnet is very
50 MILES
FIGURE 1.?Location of the three kimberlite pipes studied.
FIGURE 2.?Location of the
Garnet Ridge kimberlite
pipes.
I**
PER CENT CBLCIUM
10
FIGURE 3.?The calcium content of Garnet Ridge garnets plotted against chromium content.
X garnets from Garnet Ridge A garnet inclusions in diamond
NUMBER 19
sparsely distributed through the weathered kimber-
lite. Fortunately, the garnet has been substantially
concentrated in numerous ant hills that dot the
outcrops.
Samples of this natural concentrate were collected
at the three localities. The garnet was further con-
centrated in the laboratory and sorted into color
groups. Microprobe analyses were then made of
811 grains, for Ca, Mg, and Cr, using an ARL EMX
microprobe. Most of these same grains were later
analyzed on a nine channel ARL SEMQ micro-
probe. Operating conditions were 15KV, 0.15JAA.
Standards used were: for Si, Al, Mg, Ca-pyrope from
Kakanui, New Zealand; for Ti-hornblende from
Kakanui, New Zealand; for Cr-chromite from the
Stillwater Complex, Montana. The complete
analyses were corrected by the method of Bence
and Albee.
Diamond Inclusion Field
The eclogitic garnets that have been found as in-
clusions in diamond are low in chromium content
and, therefore, indistinguishable from garnet from
CR20 40 60 80
FIGURE 4.?Ca-Mg-Cr diagram.
X garnets from Garnet Ridge A garnet inclusions in diamond
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 2.?Analyses of Garnet Ridge garnets (from ant hills)
(digits in parentheses identify grain number)
Constituent
TiO,,2
2 3
FeO*
MnO
MgO
CaO
Total
1
(12-10)
37.3
21.9
<0.1
31.8
3.9
3.8
1.3
100.0
2 3 4 5 6
(12-8)(22-12)(24-13)(23-5)(24-3)
39.5
22.6
<0.1
21.5
2.8
11.6
1.3
99.3
43.5
23.3
1.3
6.0
0.16
22.5
2.3
99.1
42.7
0.13
22.6
3.0
7.1
0.25
21.6
4.0
101.4
42.5
<0.1
21.8
3.8
6.4
0.21
21.6
3.5
99.8
41.3
0.17
20.4
5.2
8.9
0.39
20.2
4.6
101.2
7
(25-6)
41.7
<0.1
20.5
5.4
7.8
0.37
19.6
5.1
100.5
8
(2-3)
41.6
<0.1
19.3
6.4
8.1
0.37
18.3
6.4
100.5
9
(2-1)
41.5
0.18
18.6
6.5
9.3
0.39
16.4
7.1
100.0
10
(2-9)
41.0
<0.1
19.5
6.1
8.9
0.37
17.1
6.8
99.8
11
(2-7)
41.6
0.13
20.0
5.8
7.6
0.29
19.2
6.1
100.7
12 13 14
(2-6)(22-16)(25-18
41.6
<0.1
19.8
5.7
8.0
0.30
18.9
5.5
99.8
42.0
0.1
20.1
4.4
8.4
0.36
18.2
5.5
99.1
42.4
<0.1
20.3
4.6
7.3
0.25
19.5
6.5
100.9
ATOMIC PROPORTIONS ON
Si ..
Ti ..
Al ..
Cr . .
Fe2+
Mn ..
Mg ..
Ca ..
2.98 3.00 3.05
0.00 0.00 0.00
2.06 2.02 1.93
0.00 0.00 0.07
2.12 1.37 0.35
0.26 0.18 0.01
0.45 1.31 2.35
0.11 0.11 0.17
2.98 3.01 2.95 2.99 3.00 3.04 3.00 2.98 3.01 3.05 3.02
0.01 0.00 0.01 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00
1.86 1.82 1.72 1.73 1.64 1.60 1.68 1.69 1.69 1.72 1.70
0.17 0.21 0.29 0.31 0.37 0.38 0.35 0.33 0.33 0.25 0.26
0.41 0.38 0.53 0.47 0.49 0.57 0.54 0.46 0.48 0.51 0.43
0.01 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02
2.25 2.28 2.15 2.09 1.97 1.79 1.86 2.05 2.04 1.97 2.07
0.30 0.27 0.35 0.39 0.50 0.56 0.53 0.47 0.43 0.43 0.50
*Total iron calculated as FeO
eclogite xenoliths. Of greater significance are the
peridotitic garnets found as inclusions in diamond,
characterized by high Mg, low Ca and Al, and
high Cr. Analyses of these garnets (Table 1) from
Gurney and Switzer (1973, table 4) and Lawless
(1974, table 54), have been used to delineate the
"diamond inclusion field" in the plots of garnet
compositions for the three localities studied.
Garnet Ridge
Garnet Ridge was named for abundant garnet
xenocrysts found in four kimberlite pipes that in-
trude Jurassic age rocks about 35 miles [56 km]
northeast of Kayenta, Arizona (Figure 1). Three of
the pipes lie in a cluster just north of U.S. High-
way 164, about 10 miles [16 km] east of Dinnehotso
(Figure 2). A fourth pipe lies at the ridge crest 2i/2
miles [4 km] west of the other three.
Garnet was collected at all four pipes, but since
preliminary work failed to reveal any differences
between them, the results were combined.
A total of 361 garnet xenocrysts were analyzed
for Ca, Mg, and Cr, of which 250 complete analyses
were made. Complete analyses for 31 are given in
Table 2 to show the complete compositional range
encountered. The highest chromium content (6.5%
Cr2O3) was found in the dark lilac color group.
All of the partial analyses are plotted on the Ca-Cr
diagram, and the 250 complete analyses are plotted
on the ternary diagrams (Figures 3-5).
GARNET MASSES.?Abundant in all of the Garnet
Ridge pipes (but absent at Buell Park and Green
Knobs) are pieces of brown, nearly monomineralic,
polycrystalline garnet, sometimes of large size.
Gregory (1916) reported finding pieces of this ma-
NUMBER 19
15 16 17 18 19 20 21 22 23 24 25 26 2? 28 29 30 31
(25-17)(19-11)(20-2) (19-1)(13-10) (11-3)(13-5) (13-4)(13-8)(14-4)(28-1)(25-13)(21-1)(26-14)(26-7)(2-2)(11-9)
41.2 42.4 41.6
0.26 <0.1 0.10
20.7
3.6
12.9
0.45
16.6
5.1
22.4 23.2
1.8 1.2
9.9 11.1
0.32 0.35
18.9 19.1
5.0 2.9
42.8 41.7 39.6 42.1 40.8 40.6 40.2 39.6 39.9 41.8 39.8 40.6
<0.1 0.14 <0.1 0.13 <0.1 0.11 <0.1 <0.1 0.11 0.15 0.14 <0.1
23.9 24.1 21.4 23.4 22.1 21.9 21.9 21.5 20.4 22.3 21.7 22.7
0.52 <0.1 <0.1 0.11 <0.1 0.11 <0.1 <0.1 2.1 1.9 1.5 0.65
8.4 11.4 24.8 9.5 17.5 13.9 14.7 16.1 15.4 9.9 15.3 14.1
0.26 0.28 0.44 0.24 0.25 0.24 0.20 0.22 0.45 0.37 0.42 0.35
20.2 18.8 8.4 18.3 11.6 11.1 9.8 8.1 13.2 18.5 14.2 16.2
4.1 3.6 6.2 6.0 8.5 11.4 12.6 13.7 8.0 3.6 6.6 5.1
40.6
0.16
21.9
2.8
13.0
0.38
15.3
6.3
37.9
<0.1
21.2
<0.1
27.8
0.89
4.0
8.5
I0O.8 100.7 99.6 100.2 100.0 100.8 99.8 100.8 99.4 99.4 99.2 99.6 98.5 99.7 99.7 100.4 100.3
BE BASIS OF 12 OXYGENS
3.00 3.02 2.99 3.02 2.98 3.02 3.01 3.02 3.03 3.02 3.01 2.99 3.03 2.96 2.97
O.Ol 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.00 0.01 0.01 0.01 0.00
1.77 1.88 1.97 1.99 2.03 1.92 1.97 1.93 1.93 1.94 1.93 1.80 1.91 1.90 1.96
0.21 0.10 0.07 0.03 0.00 0.00 0.01 0.00 0.01 0.00 0.00 0.12 0.11 0.09 0.04
0.78 0.59 0.67 0.50 0.68 1.58 0.57 1.08 0.87 0.92 1.03 0.97 0.60 0.95 0.86
0.O3 0.02 0.02 0.02 0.02 0.03 0.01 0.02 0.02 0.01 0.01 0.03 0.02 0.03 0.02
1.80 2.00 2.05 2.12 2.00 0.95 1.95 1.28 1.23 1.10 0.92 1.48 2.00 1.57 1.77
0.40 0.38 0.22 0.31 0.28 0.51 0.46 0.67 0.91 1.01 1.12 0.64 0.28 0.53 0.40
2.97
0.01
1.89
0.16
0.79
0.02
1.67
0.49
2.99
0.00
1.97
0.00
1.83
0.06
0.47
0.72
terial up to four inches [10 cm] in diameter. The
writer found numerous fragments up to 2 cm in
size, and in Pipe No. 2 a piece 11 X 7 X 5 cm
weighing 515 grams. Texturally it is equigranular
massive, with grain size 0.5-1 mm. Analyses of two
specimens are given in Table 3. The first (column
1) contains minor rutile. The second (column 2)
contains rutile and ilmenite.
XENOLITHS.?Xenoliths of two kinds are very
abundant in the Garnet Ridge pipes: (1) breccia
blocks of sedimentary rocks, some several hundred
feet long, have subsided as much as 1200 feet into
the pipes, and (2) pebble to boulder size crystalline
rocks from more than 4000 feet below (Malde and
Thaden, 1963).
The wide variety of garnetiferous xenoliths found
in the Garnet Ridge pipes has been described by
Malde and Thaden (1963), O'Hara and Mercy
(1966), and Watson and Morton (1969). Of partic-
ular interest are the rare eclogite xenoliths. An un-
usually large example, found by the writer in Pipe
No. 2, is a well-rounded nodule with dimensions
16 X 13 X 8 cm and weighing 2.55 kg. Analyses
of the garnet from this, and from another smaller
eclogite xenolith from the same pipe, are given in
Table 3, columns 3 and 4. In columns 5-8 are given
analyses of eclogite garnets from Garnet Ridge by
O'Hara and Mercy (1966) and Watson and Morton
(1969).
Buell Park
The Buell Park kimberlite pipe is about 30 km
north of Fort Defiance, Arizona (Figure 6). This
pipe, diameter 4.5 km, is apparently the largest in
the world.
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
Cfl
20
40 .60
FE20 40 60 80
FIGURE 5.?Ca-Mg-Fe diagram.
X garnets from Garnet Ridge A garnet inclusions in diamond
The Buell Park pipe now forms a basin underlain
largely by kimberlite tuff breccia (Schmitt, Swann,
and Smith, 1974). A ring-dike of olivine-bearing
minette forms a ridge, known as Peridot Ridge,
that curves across the southeast quadrant of the
basin. It was from ant hills on the slopes of this
ridge that the samples were collected for this study.
Garnet-bearing xenoliths are rare and no eclogite
xenoliths have been found (Schmitt, Swann, and
Smith, 1974).
Of a total of 227 xenocrysts analyzed for Ca, Mg,
and Cr, complete analyses were made of 179. Com-
plete analyses for 37 of these are given in Table 4
to show the compositional range found in Buell
Park garnets. The highest chromium content (5.1%
Cr2O3) was found in xenocryst having a pink
color. Thirty lilac color grains gave chromium con-
tents ranging from 1.4% to 2.6%. All of the partial
analyses are plotted on the Ca-Cr diagram, and the
complete analyses are plotted on the ternary dia-
grams (Figures 7-9).
Garnet xenocrysts of varying color are present
in kimberlite tuff matrix, and they have the same
mixed origin as the detrital grains in the soil.
NUMBER 19
TABLE 3.?Analyses of garnet from Garnet Ridge xenoliths
Constituent 10 11 12 13
SiO,
TiO,
A12?3
FeO
MnO
MgO
CaO
39.7
<0.1
22.4
23.3*
0.58
9.8
5.4
40.7
<0.1
22.3
0.44
15.4*
0.24
10.5
11.5
39.7
20.5
26.7*
1.9
6.1
4.7
38.0
22.1
29.6*
0.61
6.3
4.5
38.10
0.09
21.89
0.017
1.47
26.62
0.82
5.69
5.66
101.3 101.1 99.8 101.0 100.36
37.53
1.38
20.65
0.00
0.00
30.54
1.05
2.95
5.51
99.61
38.91
0.00
21.34
0.00
0.30
27.91
1.04
5.79
4.29
99.58
38.51
0.00
21.12
0.00
29.94
0.83
5.26
3.89
39.6
0.00
23.4
19.9*
0.68
14.9
1.7
39.3
0.10
20.6
0.13
23.9*
0.41
8.3
6.1
37.4
21.7
27.1*
0.73
6.4
6.6
99.55 100.3 98.8 100.1
37.6
21.1
28.9*
0.51
5.4
6.1
99.6
37.9
0.12
20.8
28.9*
0.61
4.9
6.7
99.9
Si
Ti
Al
Cr
Fe3+
Fe2+
Mn
Me
Ca
2.99
0.00
1.99
0.00
1.47
0.04
1.10
0.44
3.01
0.00
1.94
0.03
0.95
0.02
1.16
0.91
3.
0.
1
n
i
0.
0.
0.
10
00
89
nn
74
71
39
ATOMIC PROPORTIONS ON
2.95
0.00
2.02
0.00
1.92
0.04
0.73
0.37
2.97
0.01
2.01
0.00
0.09
1.73
0.05
0.66
0.47
3.00
0.08
1.94
0.00
0.00
2.04
0.07
0.35
0.47
THE BASIS
3.05
0.00
1.97
0.00
0.02
1.83
0.07
0.68
0.36
OF 12
3.04
0.00
1.96
0.00
1.98
0.06
0.62
0.33
OXYGENS
2.94
0.00
2.05
0.00
1.23
0.04
1.65
0.14
3.05
0.01
1.89
0.01
1.55
0.03
0.96
0.51
2.93
0.00
2.01
0.00
1.78
0.05
0.75
0.55
2.97
0.00
1.97
0.00
1.91
0.03
0.64
0.52
2
0
1
n
i
n
n
0
.99
.01
94
nn
91
04
,S8
.57
* Total Fe calculated as FeO.
Column 1: Garnet mass (garnet with minor rutile), 113094/24.
Column 2: Garnet mass (garnet with minor rutile and ilmenite), 113094/4.
Column 3: Eclogite, 113049/28.
Column 4: Eclogite, 113049/7.
Column 5: Eclogite (O'Hara and Mercy, 1966, table 6).
Columns 6-8: Eclogite (Watson and Morton, 1966, table 5).
Column 9: Garnet-quartz-talc schist, 113094/1.
Column 10: Garnet-plagioclase amphibolite, 113094/72.
Column 11: Garnet amphibolite, 113094/25.
Column 12: Garnet-hornblende gneiss, 113094/23.
Column 13: Garnet-hornblende gneiss, 113094/5.
Analyses of four such grains picked from a single
hand-specimen of dark gray-green, friable kimber-
lite tuff are given in Table 5. The one with the
highest chromium content is dark red in color.
Green Knobs
Green Knobs is a kimberlite pipe lying 6 km
northeast of Buell Park in New Mexico, near the
northern end of Red Lake (Figure 6). It has a di-
ameter of approximately 0.8 km and contains only
kimberlite tuff-breccia and abundant xenoliths
(Schmitt, Swann, and Smith, 1974). Gneissic, gab-
broic, and ultrabasic xenoliths are abundant, but
none collected by the writer contained garnet.
O'Hara and Mercy (1966) also report finding no
garnetiferous xenoliths, other than one small frag-
ment of clinopyroxene rock containing 2% of pale
pink garnet.
A total of 236 garnet grains were analyzed for
Ca, Mg, and Cr. Complete analyses were made of
174 of these same xenocrysts, of which 29 analyses
are given in Table 6 to show the compositional
range found. The highest chromium content, 5.9%
35'50' I L
FIGURE 6.?Location of the Buell Park
and Green Knobs kimberlite pipes.
rFOKT DEFIANCE
6 MILES
6..
3..
FIGURE 7.?The calcium content of Buell
Park garnets plotted against chromium.
X garnets from Buell Park
A garnet inclusions in diamond
2..
PER CENT CHLCIUM
NUMBER 19 11
20
40
CR20 40 60
FIGURE 8.?Ca-Mg-Cr diagram.
X garnets from Buell Park A garnet inclusions in diamond
80
12 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 4*?Analyses of Buell Park garnets (from ant hills)
(digits in parentheses identify grain number)
Constituent
in2
to,,2
'V3
Cr^O2 3
FeO
MnO
MgO
CaO
Total
1
(8-4)
41.2
0.13
23.9
0.17
11.9
0.26
18.0
4.5
100.2
2
(1-8)
42.3
0.11
22.2
1.9
9.8
0.32
18.0
4.9
99.5
3
(10-6)
41.8
0.13
22.7
1.6
9.2
0.31
18.7
5.2
99.8
4
(3-3)
42.4
<0.1
23.7
1.1
6.6
0.20
20.9
5.1
100.1
5
(1-5)
41.7
0.16
23.0
1.6
9.5
0.29
18.8
5.1
100.1
6
(3-6)
42.7
<0.1
23.9
0.41
11.8
0.20
17.0
5.1
101.2
7
(11-1)
41.9
<0.1
21.6
2.9
9.6
0.32
17.5
5.4
99.2
8 9
(1-7)(13-18)
42.3
<0.1
22.3
2.7
9.7
0.35
17.4
5.3
100.2
42.0
<0.1
20.8
3.2
9.8
0.35
18.1
5.5
99.8
10
(2-9)
42.5
<0.1
22.3
2.4
9.1
0.33
18.1
5.5
100.4
11
(3-5)
43.0
0.10
23.4
1.1
9.1
0.29
18.6
5.6
101.2
12 13
(12-19)(2-2)
41.5
<0.1
22.0
2.6
9.6
0.32
18.6
5.5
100.3
42.1
<0.1
22.5
3.0
8.2
0.30
19.2
5.5
100.8
14
(2-1)
42.6
<0.1
22.3
2.6
8.3
0.28
18.3
5.6
100.2
15
(4-5)
43.2
<0.1
23.1
0.51
8.1
0.22
19.2
5.8
100.3
16 17
(2-7)(13-1)
42.5
<0.1
21.7
3.3
8.0
0.29
19.0
5.8
100.7
40.9
0.12
22.0
2.2
11.1
0.40
17.1
5.8
99.6
ATOMIC PROPORTIONS ON
Si
Ti ,
Al
Cr
Fe
Mn
Me
Ca
2.96
0.01
2.03
0.01
0.72
0.02
1.93
0.35
3.
0.
1.
0.
0.
0.
1.
0.
04
01
88
11
59
02
93
38
3.
0.
1.
0.
0.
0.
7.
0.
00
01
92
09
55
02
00
40
2.
0.
1.
0.
0.
0.
2.
0.
99
00
97
06
39
01
19
39
2.98
0.01
1.94
0.09
0.57
0.02
2.00
0.39
3.03
0.00
2.00
0.02
0.70
0.01
1.80
0.39
3.04
0.00
1.84
0.17
0.58
0.02
1.89
0.42
3.04
0.00
1.89
0.15
0.58
0.02
1.86
0.41
3.04
0.00
1.77
0.18
0.59
0.02
1.95
0.43
3
0
1
0
0
0
1
0
.04
.00
.88
.14
.54
.0?
.93
.42
3.03
0.01
1.94
0.06
0.54
0.02
1.95
0.42
2.98
0.00
1.86
0.15
0.58
0.02
1.99
0.42
2.99
0.00
1.88
0.17
0.49
0.02
2.03
0.42
3.04
0.00
1.88
0.15
0.50
0.02
1.95
0.43
3.06
0.00
1.93
0.03
0.48
0.01
2.02
0.44
3.02
0.00
1.82
0.19
0.48
0.02
2.01
0.44
2.98
0.01
1.89
0.13
0.63
0.02
1.86
0.45
NUMBER 19 13
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
(8-5)(14-l) (2-8) (4-3) (4-8) (3-8) (3-9) (5-7) (7-3) (4-1) (8-6) (14-10)(15-1)(6-1) (6-8) (15-2) (8-1) (7-1)(15-5) (15-15)
42.1
0.12
23.8
0.16
9.0
0.20
18.5
6.1
41.8
<0.1
20.1
4.9
7.4
0.26
18.8
6.5
43.2
<0.1
21.2
4.4
7.7
0.30
18.3
6.4
42.1
<0.1
24.5
0.27
11.3
0.28
15.8
6.5
42.3
<0.1
22.7
0.21
11.9
0.24
15.2
7.5
41.9
0.10
23.2
0.97
9.0
0.21
17.4
7.9
42.5
<0.1
22.8
1.1
8.9
0.27
16.6
7.8
42.3
<0.1
22.9
0.25
10.7
0.21
14.9
8.3
42.5
0.11
22.9
0.16
11.8
0.21
14.2
8.6
42.6
<0.1
22.6
0.59
7.2
0.18
16.7
8.9
41.3
<0.1
22.8
0.14
12.4
0.18
13.5
10.0
42.1
0.16
19.5
5.1
8.2
0.32
16.2
8.9
41.3
0.10
22.6
<0.1
13.7
0.23
13.1
9.2
42.4
<0.1
22.1
0.20
11.9
0.21
12.7
9.7
42.1
<0.1
22.9
0.24
11.6
0.20
13.4
10.4
41.2
0.10
23.0
0.17
12.3
0.18
12.7
10.8
41.4
<0.1
23.0
<0.01
9.9
0.17
13.8
12.2
40.6
0.10
21.3
0.11
16.6
0.26
9.2
11.2
40.1
0.13
22.2
0.13
14.2
0.23
10.8
12.1
41.8
<0.1
22.9
<0.1
8.6
0.18
13.9
13.2
100.0 99.8 101.5 98.7 100.1 100.7 100.1 99.6 100.5 98.8 l 100.2 100.5 100.3 99.3 100.9 100.5 100.7 99.5 99.8 100.7
IHE BASIS OF
3.00
0.01
2.00
0.01
0.54
0.01
1.96
0.47
3.02
0.00
1.71
0.28
0.45
0.02
2.02
0.50
12 OXYGENS
3.05
0.00
1.76
0.25
0.45
0.02
1.93
0.48
3.01
0.00
2.06
0.02
0.67
0.02
1.68
0.50
3.06
0.00
1.94
0.01
0.72
0.01
1.64
0.58
2.99
0.01
1.95
0.05
0.54
0.01
1.85
0.60
3.05
0.00
1.93
0.06
0.53
0.02
1.77
0.60
3.07
0.00
1.96
0.01
0.65
0.01
1.61
0.64
3.07
0.01
1.95
0.01
0.71
0.01
1.53
0.67
3.07
0.00
1.92
0.03
0.43
0.01
1.79
0.69
3.01
0.00
1.96
0.01
0.76
0.01
1.47
0.78
3.05
0.01
1.66
0.29
0.50
0.02
1.75
0.69
3.03
0.01
1.95
0.00
0.84
0.01
1.43
0.72
3.11
0.00
1.91
0.01
0.73
0.01
1.39
0.76
3.04
0.00
1.95
0.01
0.70
0.01
1.44
0.81
3.01
0.01
1.98
0.01
0.75
0.01
1.38
0.84
3.00
0.00
1.97
0.00
0.60
0.01
1.49
0.95
3.07
0.01
1.90
0.01
1.05
0.02
1.04
0.91
2.99
0.01
1.95
0.01
0.89
0.01
1.20
0.97
3.02
0.00
1.95
0.00
0.52
0.01
1.49
1.02
14 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
20
FE20 40 60 30
FIGURE 9.?Ca-Mg-Fe diagram.
X garnets from Buell Park A garnet inclusions in diamond
10,.
9..
8..
7..
6..
3..
2..
FIGURE 10.?The calcium content
of Green Knobs garnets plotted
against chromium content.
X garnets from Green Knobs
A garnet inclusions in diamond
PER CENT CRLCIUM
TABLE 5.?Analyses of Buell Park garnets in Kimberlite tuff
Constituent
SiO
TiO2
A12?3
Cr2?3
FeO *
MnO
MeO
CaO
1
38.6
0.12
21.5
0.11
25.2
0.57
7.5
6.5
100.1
2
39.5
<0.1
22.2
<0.1
29.0
0.47
8.6
1.8
101.6
3
41.6
<0.1
23.4
0.43
12.4
0.28
17.3
4.6
100.0
4
41.4
<0.1
21.5
4.1
9.0
0.30
18.5
5.6
100.5
ATOMIC PROPORTIONS ON THE BASIS OF 12 OXYGENS
Ti
Al
Cr
Fe
Mg
Ca '
2.98
0.01
1.96
0.01
1.63
0.04
0.86
0.54
3.01
0.00
1.99
0.00
1.85
0.03
0.98
0.15
3.00
0.00
1.99
0.03
0.75
0.02
1.86
0.36
2.97
0.00
1.82
0.23
0.54
0.02
1.98
0.43
Cr2O3, was in a grain of dark red color. All of the
partial analyses are plotted on the Ca-Cr diagram,
and the complete analyses are plotted on the ter-
nary diagrams (Figures 10-12).
As at Buell Park, garnet xenocrysts of several
colors may be seen in the kimberlite tuff. Analyses
of six garnet grains picked from a single hand-
specimen are given in Table 7. The one with the
highest chromium content, 2.5% Cr2O3, is red in
color.
Discussion
In garnets from garnet periodotites the calcium
and chromium contents increase sympathetically.
Plots of calcium against chromium for garnet xeno-
crysts from Garnet Ridge, Buell Park, and Green
Knobs (Figures 3, 7, 10) show that garnets from
the peridotite suite predominate in these kimber-
lites. The points having between 4% and 10%
calcium but little chromium, and therefore plotting
close to the X axis, are eclogite garnets. At Garnet
*Total iron calculated as FeO.
16 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 6.?Analyses of Green Knobs garnets (from ant hills)
Con-
stit-
uent
Si02
TiO2
A12O3
Cr2?3
FeO*
MnO
MgO
CaO
Total
1 2
(12-3)(10-10)
39.2
<0.1
23.0
<0.1
22.9
0.93
12.4
2.1
100.7
41.4
0.14
23.3
0.19
13.6
0.22
17.5
4.2
100.6
3
(9-2)
41.6
<0.1
22.5
0.76
12.6
0.31
17.7
4.8
100.1
4
(5-3)
41.9
0.21
22.6
1.3
9.6
0.32
19.3
5.0
100.2
5
(11-2)
41.5
<0.1
23.8
0.12
15.0
0.23
16.0
5.1
101.8
6
(2-10)
42.1
0.14
22.6
2.2
9.6
0.32
19.2
5.3
101.4
7
(2-2)
41.5
<0.1
22.2
2.7
9.3
0.33
18.8
5.5
100.3
8
(3-5)
41.1
<0.1
21.0
3.9
8.7
0.36
18.7
5.7
99.5
9
(3-8)
41.5
<0.1
21.4
4.2
8.7
0.31
18.5
5.8
100.6
10
(6-2)
41.2
<0.1
23.4
0.81
9.7
0.32
18.0
5.8
99.3
11
(7-5)
41.8
<0.1
23.2
0.31
12.1
0.21
16.0
6.3
99.9
12
(1-4)
41.0
0.24
21.1
2.4
11.9
0.38
16.3
7.0
100.4
13
(1-3)
41.3
<0.1
19.6
5.9
8.9
0.37
17.3
7.0
100.5
14
(18-12)
40.9
0.23
20.5
3.3
13.4
0.44
15.4
6.8
101.0
ATOMIC PROPORTIONS ON
Si
Ti
Al
Cr
Fe
Mn
Mg
Ca
2.94
0.00
2.04
0.00
1.44
0.06
1.39
0.17
2.98
0.01
1.98
0.01
0.82
0.01
1.88
0.32
3.00
0.00
1.92
0.04
0.76
0.02
1.91
0.37
2.99
0.01
1.90
0.07
0.57
0.02
2.05
0.38
2.98
0.00
2.01
0.01
0.90
0.01
1.71
0.39
2.98
0.01
1.89
0.12
0.57
0.02
2.03
0.40
2.97
0.00
1.88
0.15
0.56
0.02
2.01
0.42
2.98
0.00
1.79
0.22
0.53
0.02
2.02
0.44
2.98
0.00
1.81
0.24
0.52
0.02
1.98
0.45
2.98
0.00
1.99
0.05
0.59
0.02
1.94
0.45
3.02
0.00
1.98
0.02
0.73
0.01
1.73
0.49
2.99
0.01
1.81
0.14
0.73
0.02
1.77
0.55
3.00
0.00
1.68
0.34
0.54
0.02
1.87
0.54
2.99
0.01
1.77
0.19
0.82
0.03
1.68
0.53
*Total Fe calculated as FeO
TABLE 7.?Analyses of Green Knobs garnets in kimberlite tuff
Constituent
TiO2
A12?3
Cr2?3
FeO*
MnO ..
MgO ..
CaO ..
Si
Ti
Al
Cr
Fe
Mn
41.5
0.15
22.7
0.14
15.0
0.42
11.9
9.8
101.6
39.2
0.13
21.4
<0.1
27.8
0.34
6.5
5.9
40.8
0.16
22.4
0.17
14.9
0.26
11.9
10.0
41.3
<0.1
23.0
1.3
11.8
0.24
14.4
9.4
40.0
<0.1
22.8
<0.1
23.8
0.48
12.5
1.3
101.3 100.6 101.4 100.9
22.6
2.5
9.9
0.31
17.9
5.0
99.8
ATOMIC PROPORTIONS ON THE BASIS OF 12 OXYGENS
3.02
0.01
1.95
0.01
0.91
0.03
1.29
0.77
3.02
0.01
1.94
0.00
1.79
0.02
0.75
0.49
3.01
0.01
1.95
0.01
0.92
0.02
1.31
0.79
2.98
0.00
1.96
0.07
0.71
0.02
1.55
0.73
2.99
0.00
2.01
0.00
1.49
0.03
1.39
0.10
3.00
0.00
1.92
0.14
0.60
0.02
1.92
0.39
*Total iron calculated as FeO.
NUMBER 19 17
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
(6-1) (18-4) (1-1) (7-3) (18-2) (1-2) (10-9)(18-13) (11-1) (9-1) (10-5) (7-7) (11-6)(18-14)(21-14)
42.0
0.10
23.4
0.48
9.3
0.25
17.4
6.8
99.7
41.0
0.24
20.9
2.8
12.7
0.39
15.4
7.4
100.8
THE BASIS OF
3.01
0.01
1.98
0.03
0.56
0.02
1.86
0.52
2.99
0.01
1.80
0.16
0.78
0.02
1.67
0.58
40.2
0.10
21.8
1.8
13.4
0.49
14.2
7.7
99.9
41.5
<0.1
22.8
0.27
10.7
0.21
15.6
7.9
99.0
12 OXYGENS
2.97
0.01
1.90
0.11
0.83
0.03
1.57
0.61
3.03
0.00
1.96
0.02
0.65
0.01
1.70
0.62
41.2
0.25
21.6
1.9
11.4
0.32
16.0
7.8
100.5
2.99
0.01
1.85
0.11
0.69
0.02
1.73
0.61
40.7
0.26
20.8
2.9
11.9
0.38
15.4
8.0
100.4
2.98
0.01
1.80
0.17
0.73
0.02
1.68
0.63
42.2
0.19
22.3
0.62
10.2
0.21
15.9
8.1
99.7
3.05
0.01
1.90
0.04
0.62
0.01
1.71
0.63
42.2
0.18
20.8
3.5
8.3
0.27
16.6
9.0
100.7
3.03
0.01
1.76
0.20
0.50
0.02
1.78
0.69
41.9
0.12
24.0
0.19
10.1
0.25
15.8
9.1
101.5
2.98
0.01
2.01
0.01
0.60
0.02
1.68
0.69
39.8
0.17
20.9
0.11
18.4
0.33
9.6
9.9
99.4
3.03
0.01
1.88
0.01
1.17
0.02
1.09
0.81
40.5
0.11
22.5
0.15
11.3
0.20
12.8
11.3
98.8
3.00
0.01
1.97
0.01
0.70
0.01
1.41
0.90
41.1
<0.1
23.1
0.20
8.3
0.17
14.4
11.9
99.2
3.00
0.00
1.99
0.01
0.51
0.01
1.56
0.93
41.1
0.13
22.4
0.15
12.4
0.21
11.5
13.4
101.3
3.00
0.01
1.93
0.01
0.76
0.01
1.25
1.05
42.1
<0.1
22.1
3.2
9.0
0.32
19.0
5.8
101.5
2.98
0.00
1.85
0.18
0.53
0.02
2.01
0.44
41.9
<0.1
22.1
0.32
6.2
0.17
14.0
13.9
98.6
3.06
0.00
1.90
0.02
0.38
0.01
1.52
1.09
TABLE 8.?Garnet from garnet peridotite xenoliths from
South African kimberlite pipes (Gurney and Switzer, 1973,
table 1)
Constituent
Ti0n
FeO*
MnO .
MgO .
CaO .
42.23
0.02
22.83
2.13
8.45
0.38
20.50
4.41
100.95
42.80
0.02
23.35
1.75
8.55
0.40
20.56
4.28
41.79
0.03
22.56
2.13
8.51
0.36
20.57
4.45
42.26
0.02
22.37
2.49
7.97
0.40
20.51
4.45
41.95
0.13
19.71
5.38
7.26
0.35
20.47
5.24
41.45
0.27
20.68
4.17
7.07
0.35
20.63
4.58
101.71 100.40 100.47 100.91 99.20
ATOMIC PROPORTIONS ON THE BASIS OF 12 OXYGENS
2+
2.98
0.00
1.90
0.12
0.50
0.02
2.99
0.00
1.92
0.10
0.50
0.02
2.97
0.00
1.89
0.12
0.51
0.02
2.99
0.00
1.87
0.14
0.47
0.02
3.00
0.01
1.66
0.30
0.43
0.02
2.98
0.02
1.76
0.24
0.43
0.02
*Total iron calculated as TeO.
18 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
20
40 ?0
CR20 40 60 80
FIGURE 11.?Ca-Mg-Cr diagram.
X garnets from Green Knobs A garnet inclusions in diamond
Ridge and Green Knobs a few xenocrysts with be-
tween 1% and 2% calcium and very low chromium
are high in ferrous iron and are almandines de-
rived from basement igneous or metamorphic rocks.
At Garnet Ridge a few scattered points to the
left of the garnet peridotites trend approach in
composition the low calcium-high chromium con-
tent characteristic of diamond inclusion garnets.
None fall well within the diamond inclusion field,
however, and it is not possible to say that they have
a deeper origin than the common garnet peridotite
garnet.
Figure 13 is a Ca-Mg-Fe plot of garnets from
three rock groups: (1) eclogite xenoliths from Gar-
net Ridge, (2) metamorphic rocks from Garnet
Ridge, and (3) garnet peridotite xenoliths from
South Africa kimberlites. The analyses are given
in Tables 3 and 8.
Comparison of Figure 13 with the Ca-Mg-Fe
plots of garnet xenocrysts from Garnet Ridge, Buell
NUMBER 19 19
20
40
60
80
FE20 40 60 80
FIGURE 12.?Ca-Mg-Fe diagram.
X garnets from Green Knobs A garnet inclusions in diamond
Park, and Green Knobs shows again that most of
the garnet in these kimberlites have a composition
characteristic of garnets from garnet peridotite and
were probably derived from disaggregated garnet
peridotite xenoliths.
The provenance of the eclogite xenoliths at
Garnet Ridge presents an interesting problem.
Since they are found in kimberlite pipes, they
would fall in group A of Coleman, et al. (1965).
Instead, as pointed out by Watson and Morton
(1969), the garnets in Garnet Ridge eclogites have
a composition that places them in Coleman's group
C, suggesting that the Garnet Ridge xenoliths came
from a glaucophane schist facies in the basement
rocks. Other factors, however, discussed in detail by
Watson and Morton, lead them to conclude that
the Garnet Ridge eclogite has come from the deep
crust or upper mantle. O'Hara and Mercy (1966)
concluded that the Garnet Ridge eclogite xenoliths
are extremely sodic and not comparable to pre-
20 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
20 80
40 60
60 40
20
20 40 60 80
FIGURE 13.?Ca-Mg-Fe diagram. (The analyses are given in Tables 3 and 8.)
? eclogite xenoliths from Garnet Ridge
O other garnetiferous rocks from Garnet Ridge
? garnet peridotite xenoliths from South African kimberlite pipes
viously described material from any source.
The large garnet masses found at Garnet Ridge
have a composition similar to garnet from the
eclogite xenoliths, indicating that they came from
the same source, perhaps from garnet cumulates.
The Ca-Mg-Cr plot of Garnet Ridge xenocrysts
(Figure 4) shows three analyses that lie on the
border of the diamond inclusion field, but none
within it. For Buell Park and Green Knobs there
are no analyses in or near the diamond inclusion
field.
It is not possible to draw any broad conclusions
from these data for two reasons: (1) the number of
xenocrysts analyzed from each locality is small, and
(2) the true extent of the diamond inclusion field
is not yet known because of the limited data avail-
able.
From this study one could conclude that none of
NUMBER 19 21
the three kimberlite pipes examined is diamond-
iferous. If they were prospected on the basis of
garnet composition, Garnet Ridge is the one most
likely to contain diamond, while on the basis of
size Buell Park is the most likely, since in any
cluster of diamondiferous pipes the largest is also
the most economic.
Literature Cited
Balk, R.
1954. Kimberlitic Tuff Plugs in Northeastern Arizona.
Transactions of the American Geophysical Union,
35:385.
Balk, R., and M. S. Sun
1954. Petrographic Descriptions of Igneous Rocks. In
J. E. Allen and Robert Balk, editors, Mineral Re-
sources of Fort Defiance and Tohatchi Quadrangles,
Arizona and New Mexico. New Mexico Bureau of
Mines and Mineral Resources Bulletin, 36:100-118.
Coleman, R. G., D. E. Lee, L. B. Beatty, and W. W. Brannock
1965. Eclogites and Eclogites: Their Differences and Sim-
ilarities. Geological Society of America Bulletin,
76:482-508.
Gavasci, A. T., and H. Helmstaedt
1969. A Pyroxene-rich Garnet Peridotite in an Ultramafic
Breccia Dike at Moses Rock, Southeastern Utah.
Journal of Geophysical Research, 74:6691-6695.
Gavasci, Anna T., and Paul F. Kerr
1968. Uranium Emplacement at Garnet Ridge, Arizona.
Economic Geology, 63:859-875.
Gregory, H. E.
1916. Garnet Deposits of the Navajo Reservation, Arizona
and Utah. Economic Geology, 11:223-230.
1917. Geology of the Navajo Country: A Reconnaissance
of Parts of Arizona, New Mexico and Utah. United
States Geological Survey Professional Paper, 93:93-
95, 102, 146-147.
Gurney, J. J., and G. S. Switzer
1973. The Discovery of Garnets Closely Related to Dia-
monds in the Finsch Pipe, South Africa. Contribu-
tions to Mineralogy and Petrology, 39:103-116.
Lawless, P. J.
1974. Some Aspects of the Geochemistry of Kimberlite
Xenocrysts. Masters Thesis, University of Capetown.
Malde, H. E.
1954. Serpentine Pipes at Garnet Ridge, Arizona. Science,
119:618.
Malde, H. E., and R. E. Thaden
1963. Serpentine at Garnet Ridge. In Irving J. Witkind
and Robert E. Thaden, editors, Geology and Ura-
nium-Vanadium Deposits of the Monument Valley
Area, Apache and Navajo Counties, Arizona. United
States Geological Survey Bulletin, 1103:54-61.
McGetchin, T. R.
1968. The Moses Rock Dike: Geology, Petrology and
Mode of Emplacement of a Kimberlite-bearing
Breccia Dike, San Juan Co., Utah. Ph.D. disserta-
tion, California Institute of Technology, Pasadena.
McGetchin, T. R., and L. T. Silver
1970. Compositional Relations from Kimberlite and Re-
lated Rocks in the Moses Rock Dike, San Juan
County, Utah. American Mineralogist, 55:1738-1771.
Meyer, H. O. A., and F. R. Boyd
1972. Composition and Origin of Crystalline Inclusions
in Natural Diamonds. Geochimica et Cosmochimica
Ada, 36:1255-1278.
Meyer, H. O. A., and D. P. Svizero
1975. Mineral Inclusions in Brazilian Diamonds. Pages
785-795 in Ahrens, Dawson, Duncan, and Erlank,
editors, Physics and Chemistry on the Earth. Volume
9. Oxford: Pergaman Press.
O'Hara, M. J., and E. L. P. Mercy
1966. Eclogite, Peridotite and Pyrope from the Navajo
Country, Arizona. American Mineralogist, 51:336-
352.
Prinz, M., D. V. Manson, P. R. Hlava, and K. Keil
1975. Inclusions in Diamonds: Garnet Lherzolite and
Eclogite Assemblages. Pages 797-815 in Ahrens,
Dawson, Duncan, and Erlank, editors, Physics and
Chemistry of the Earth. Volume 9. Oxford: Perga-
man Press.
Reagan, A. B.
1927. Garnets in the Navajo Country. American Mineral-
ogist, 12:414.
Schmitt, H. H., G. A. Swann, and D. Smith
1974. The Buell Park Kimberlite Pipe, Northeastern
Arizona. Pages 672-698 of part 2 in Karlstrom,
Swann, and Eastwood, editors, Guide to the Geol-
ogy of Northern Arizona. Boulder, Colorado: Geo-
logical Society of America.
Sobolev, N. V., M. A. Gnevushev, L. N. Mikhaylovskaya,
S. I. Futergendler, Ye. I. Shemanina, Yu. G. Lavrent'yev,
and L. N. Pospelova
1971. Composition of Garnet and Pyroxene Inclusions in
Ural Diamonds. Doklady Akademi Nauk S.S.S.R.,
198.190-193.
Sobolev, N. V., Yu. G. Lavrent'yev, L. N. Pospelova and E.
V. Sobolev.
1969. Chrome Pyrope from Yakutian Diamonds. Doklady
Academi Nauk S.S.SJI., 189:133-136.
Stuart-Alexander, D. E., E. M. Shoemaker, and H. J. Moore
1971. Geologic Map of the Mule Ear Diatreme, San Juan
Co., Utah. U.S. Geological Survey Miscellaneous Geo-
logic Investigations Map 1-674.
Watson, K. D.
1960. Eclogite Inclusions in Serpentine Pipes at Garnet
Ridge, Northeastern Arizona. Geological Society of
America Bulletin, 71:2082-2083.
1967. Kimberlite Pipes of Northeastern Arizona. Pages
261-269 in P. J. Wyllie, editor, Ultramafic and Re-
lated Rocks. New York: John Wiley and Sons, Inc.
Watson, K. D., and D. M. Morton
1969. Eclogite Inclusions in Kimberlite Pipes at Garnet
Ridge, Northeastern Arizona. American Mineral-
ogist, 54:267-285.
Abyssal Basaltic Glasses as Indicators of Magma Compositions
Gary R. Byerly, William G. Melson,
Joseph A. Nelen, and Eugene Jarosewich
ABSTRACT
A review of the literature on alteration of abyssalbasalts shows that often portions of the glassy rind
are the most representative, or least altered, ma-terial present. Separating this glass from the pala-
gonite and other alteration products provides the
material closest in chemistry to the original magmachemistry. Use of the electron microprobe allows
for analysis of only the freshest portions of theglass. Analyzing glasses by electron microprobe,
with glass standards internally mounted in the
sample discs, is shown to be a very precise technique.Examples of the homogeneity of dredged and cored
abyssal basalts, based on glass analyses by electronmicroprobe, are presented.
Introduction
Pillow basalts are the most common igneous rock
recovered from dredges or cores taken from the
ocean depths. Chemical analyses of these basalts
have played key roles in many petrogenetic and
plate tectonic models and yet considerable con-
troversy still exists over the degree to which these
analyses reflect primary igneous processes rather
than abyssal alteration processes. Many workers
have investigated the variation in chemistry within
single pillows (Paster, 1968; Corliss, 1970; Hart
1969; Melson, Thomson, and Van Andel, 1968;
Muehlenbachs and Clayton, 1972; Matthews, 1971;
Moore, 1965; Melson and Thompson, 1973; Shido,
Miyashiro, and Ewing, 1974; and Hart, Erlank, and
Gary R. Byerly, William G. Melson, Joseph A. Nelen, and
Eugene Jarosewich, Department of Mineral Sciences, Na-
tional Museum of Natural History, Smithsonian Institution,
Washington, D.C. 20560.
Kable, 1974; Melson, 1973; Thompson, 1973) or in
abyssal basalts as a function of age (Hart, 1973;
Hekinian, 1971). All workers agree that basalt is
rapidly altered in the ocean-bottom environment
but there is no general agreement on the mecha-
nisms of alteration, the products formed, or the
basaltic material that might be most representative
of the primary chemistry. Many of these studies
have concluded that alteration varies from a highly
altered glassy rim to slight alteration in pillow
cores, making the core the most popular candidate
for chemical analysis to represent the primary
chemistry. It is the theme of this paper that por-
tions of the glassy rim often remain unaltered and
when these portions can be analyzed separately they
are the material most representative of the primary
igneous chemistry. Since most abyssal basalts are
sparsely phyric (usually less than 5 percent) the glass
will be very close to the chemistry of the total rock.
Late stage gravity or flow differentiation of pheno-
crysts are reflected in the whole rock chemistry and
may confuse the primary partial melting or differen-
tiation trends. Glass chemistry appears more homo-
geneous in single igneous events and apparently is
much less effected by late stage igneous differentia-
tion. We present a model for the alteration of
pillow basalts and a technique for electron-micro-
probe analysis of basaltic glasses. Data is presented
on the homogeneity of basaltic glass within a single
thin section and within single eruptive flows.
Model for Alteration of Abyssal Pillow Basalts
Most basaltic pillows range in size from 10 cm to
several meters in diameter and are characterized by
a concentric zonal structure consisting of an outer
glassy selvage (up to 2 cm in thickness), an intcr-
22
NUMBER 19
mediate variolitic zone (0.5 to 2 cm in thickness,
predominately radiating intergrowths of submicron
sized plagioclase and pyroxene), and a microcrystal-
line core. The degree and type of alteration varies
considerably between these three zones.
Three stages of alteration are commonly recog-
nized: a high temperature or deuteric stage begin-
ning on extrusion, an intermediate temperature
stage during cooling of the pillow, and the slow,
low temperature stage of weathering and hydra-
tion. Each stage varies in alteration process, prod-
ucts formed, and zone of material most affected.
Furthermore, it is commonly impossible to assign
a given product to one of these three alteration
stages. Deuteric processes lead to some chloritization
of olivine, pyroxene, and interstital glass and prob-
able oxidation of iron oxides in pillow cores. These
alterations take place with late stage magmatic
volatiles, but probably without addition of sea-
water (Paster, 1968; Corliss, 1970). Also important
during this stage in the development of contraction
joints and cracks that later admit seawater into the
interior of the pillow.
The second stage of alteration begins as the
pillow cools to below approximately 400? C. Sea-
water begins circulating through cracks and joints
where most of the alteration occurs. This results
in formation of serpentine and iron oxides (Pas-
ter, 1968), and a variety of clay minerals, though it
is difficult to determine the temperature at which
these may have formed (Melson and Thompson,
1973).
The third stage of alteration involves the slow
weathering process once the pillow has cooled down
to normal ocean floor temperatures. Resultant prod-
ucts are hydra ted glass and further development of
clay minerals. The thickness of the hydrated rim
increases as a function of age of the pillow (Moore,
1966). Hydrated glass, or palagonite, is predomi-
nately a cryptocrystalline mixture of clay minerals
such as smectite (Melson and Thompson, 1973;
Melson, 1973). Several studies have shown that the
process of hydration in the glass is a "surface reac-
tion." No diffusion gradients are apparent from
microprobe traverses across glass-palagonite bound-
aries. Progressive hydration of the fresh glass pro-
ceeds into the pillow from the outer surface and
along cracks and joints connecting the interior of
the pillow allowing chemical exchange with sea
water. Because erosion does not continuously ex-
pose a fresh surface for hydration this process is
impeded by the crust of palagonite formed. The
presence of empty vesicles, often lined with primary
sulfides, near the palagonite glass interface is evi-
dence of the barrier of the fresh glass to diffusion
of water and partial hydration (Melson and
Thompson, 1973). Only vesicles connected to the
surface by fractures show alteration.
Corliss (1970) summarized a model for the struc-
tural and textural controls on alteration. To a
very large extent the diffusion of material to and
from reaction sites and exchange with sea water
controls alteration. The glassy margin of pillow
fragments prevents diffusion into the interior of
the glassy rind and remains largely unaltered it-
self because of its lack of grain boundaries. Joints
and cracks act as high diffusion conduits to supply
sea water to the alteration reactions in the vario-
litic and crystalline portions of the pillow. Grain
boundaries in these zones further aid in the distri-
bution of material feeding alteration reactions and
act as nucleation sites for deposition of alteration
products.
Chemical variations caused by the above reac-
tions are complex and, in spite of many studies,
are not generally agreed upon. Several points, how-
ever, seem particularly noteworthy. Early deuteric
processes probably result in oxidation of iron and
perhaps small losses of iron and magnesium to
joints and cracks (Paster, 1968). The intermediate
stage of cooling results in an addition of water and
potassium to the pillow interiors. Low temperature
reactions add water, potassium, and iron, while de-
pleting magnesium and calcium. Oxidation of iron
also occurs. Using the above criteria, published
analyses of glass-crystalline pairs from pillow frag-
ments show an increase in apparent alteration of
the crystalline material relative to glass (Paster,
1968, Corliss, 1970; Melson, 1973; Thompson, 1973;
Shido, Miyashiro, and Ewing, 1974; and Hart, Er-
lank, and Kable, 1974). Muehlenbachs and Clay-
ton (1972) present oxygen isotope data on glass-
crystalline pairs which indicate less alteration of
the glass.
This review indicates that glass, carefully sep-
arated from palagonite and other alteration prod-
ucts, provides the material closest in chemistry to
the original liquid chemistry of abyssal pillow ba-
salts.
24 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
Electron-M icroprobe Analysis
An electron-microprobe technique is a rapid and
precise technique capable of analyzing the freshest
portions of glassy material that might otherwise be
almost entirely altered. Small subsamples of glassy
material are crushed to less than 1 mm diameter
for microscopic examination. Those chips that ap-
pear freshest and display the finest glassy luster are
mounted for electron microprobe analysis. The
chips are mounted in 5 mm holes drilled around
the edge of a 25 mm diameter by 6 mm thick lexan
disc. Ten unknown glass chips are located around
the edge of the disc with the glass standard in a
central hole. Using the technique described by
Moreland (1968), the discs are polished down to a
0.5 micron finish. The discs are carbon coated,
using a Veeco V300 coater, modified by an attached
timer. The process is automatically cut off after
1.25 seconds. The conditions were arrived at ex-
perimentally and appear adequate (Table 1).
Early analyses were performed with a three
spectrometer ARL-EMX electron microprobe. Cur-
rently all glass analyses are made with an ARL-
SEMQ electron microprobe. This instrument has
six fixed spectrometers for Si, Al, Fe, Mg, Ca, and
K, and three scanning spectrometers, which are
tuned to Na, Ti, and P for basaltic glasses. Use of
nine spectrometers enables rapid analysis of a spot,
eliminating changing spectrometer positions during
analyses. This feature is also particularly useful for
samples that degrade in the beam. Sample points
with low or high counts for any of the nine ele-
ments can be immediately spotted and a re-analysis
made at an adjacent spot. A defocused beam of
about 50 micron diameter at 15 kilovolts and 0.30
microamp beam current is used. The beam current
is visually monitored at all times, using a digital
display, to insure against short period instrument
drift. The defocused beam helps decrease volatiliza-
tion of light elements. Counting time on each spot
is 10 seconds. Each analysis consists of an average
of five spots.
Since the six fixed spectrometers do not lend
themselves to detuning, some other means of meas-
uring background has to be established. In our ap-
plication a standard with average atomic number
relatively close to that of the unknowns is selected
for background determinations. Since that back-
ground is very low for major and some minor ele-
ments the error due to the background variation
is insignificant. For very low concentration, how-
ever, care must be exercised when this approach is
taken. For this study quartz was used for determi-
nation of background for Al, Fe, Mg, Ca, Ti, Na,
and P, and corundum for Si. In Table 2 back-
grounds and counts are compared between scanning
and fixed spectrometer for potassium. The potas-
sium content of abyssal basaltic glasses ranges
widely and may reach very low concentrations. Re-
sults in Table 2 show that the average values on
quartz and corundum determined above and below
peak using scanning spectrometers agree well with
those determined on the analytical x-ray spectral
line and also with those determined on the fixed
spectrometer. The difference is well within the
statistical variation of the background counts when
samples with close average atomic numbers are
used.
In addition to the background correction the
count data are further reduced by applying the
TABLE 1.?Effect of variable carbon coating time on probe results
(see text for coating procedure)
Section*
Standard..
0.50 sec.0.75 sec.
1.00 sec.Standard..
1.25 sec.1.50 sec.
Standard..
No. of
pts.
. 6
. 1+
. 12
10
9
11
11+
10
sio2
1+1.61+
0.00
39.72
1+1^55
1+1.21*
1+1.20
M203
1U.8U
0.00
1U.67
11+.90
11+.9615.10
15.37
15.12
FeO
11.58
0.00
9.81+
11.25
11.15
11.12
11.15
11.31
MgO
13.19
0.00
12.81
12.77
12.87
12.99
12.99
CaO
10.38
0.00
9.81
10.1+6
10.1+7
10.39
10.1+3
10.35
V
2.13
0.00
2.07
2.12
2.07
2.16
2.092.16
?.2o
2.56
0.00
2.562.59
2.602.60
2.552.66
TiO2
1+.95
0.00
1+.90
1+.901+.92
1+.87
1+.98
Totals
101.27
0.00
96.12
100.51
100.57100.81
100.69
100.77
Standard disc and 5 polished thin sections each containing a split of Kakanui hornblende.Three runs of the standard disc are underlined.
NUMBER 19 25
TABLE 2.?Background for potassium from scanning and fixed spectrometers
(15 kv, 0.30 M amp beam current, and average of ten 10-second counts)
Sample
Corundum . ? ?
Quartz
Springwater
01ivine
VG-611
VG-C96
VG-2
VG-A99
Adularia ...
Average
atomic No. 2Chem. anal.
Scanning Spectrometer
Below Above Fixed
peak Peak peak spectrometer
10.7
10.8
12.5
12.5
12.612.9
12.9
Ik.6
0.01*
0.20
0.80
16.9
22 ? 5
20 + 5
22 + 5
2h ? 6
22 + 5
25 ? 6
23 ? k
28 + k
18 ? 5
21 + 5
23 ? 6
32 + 6
1+6 ? 11
110 + 9
1+08 + 25
701+9 ? 65
18 ? 5
19 ? 5
23 ? 6
20 + 6
22 ? k
23 ? 6
21 + 6
30 + 6
19 ? 5
19 ? 5
23 ? 5
31+ ? 5
1+7 ? 5
103 ? 5
356 ? 21
6059 ? 99
TABLE 3.?Analyses from poorly coated disc (only background and
Bence-Albee corrections have been made)
Constituent VG-B00 VG-B01 VG-A96 VG-A97 VG-A98 VG-A99
"Best"
VG-2 VG-2
FeO ?
MgO ?
CaO ?
K20 ?
Na20 .
TiO2 .
P2?5 ?
Total
51.05 50.7^ 50.03 1+8.66 1+9.65 51.39 50.31 50.81
12.56 12.36 13.71 12.11+ 13.67 12.1+9 13.71+ 11+.06
13.18 13.10 11.35 11.19 10.( 13.25 11.26 11.81+
1+
9
0
2
1+
0
8
.88
.04
.85
.72
.06
.1+7
.81
5.06
9.09
0.82
2.63
1+.00
0.fc8
98.28
6.21+
10.80
0.67
2.38
2.95
0.3!+
98.1+7
9.71
IO.85
0.51
2.05
2.50
0.27
97.88
6.70
10.98
0.60
2.16
2.77
0.31
97.61+
5.01+
9.25
0.86
2.62
1+.01+
0.50
99.1+1+
6.63
10.7!+
0.19
2.59
1.77
0.22
97.1+5
6.71
11.12
0.19
2.62
1.85
0.20
99.1+0
TABLE 4.?Analyses from Table 3 have been normalized to the "best" chemical value of
the internal standard VG-2
Constituent VG-B00 VG-B01 VG-A96
Normalizing
VG-A97 VG-A98 VG-A99 Factors
FeO .
MgO .
CaO .
K20 .
Na20
TiO2
P2?5
Total
51.56
12.85
13.86
k.9k
9.36
0.85
2.75
k.2k
100.81+
51.21+
12.65
13.77
5.12
9.1+1
0.82
2.66
If.18
0.1+U
100.29
50.53
lU.03
11.93
6.32
11.18
O.67
2.1+1
3.08
0.31
100.1+6
1+9.11*
12.1+2
11.77
9.83
11.23
0.51
2.07
2.61
0.21+
99.82
50.05
13.99
11.36
6.78
11.37
0.60
2.18
2.90
0.28
99.51
51.90
12.78
13.93
5.10
9.58
0.86
2.65
1+.22
0.1l5
101.1+7
1.010
1.023
1.052
1.012
1.035
1.000
1.012
1.0U5
0.989
26 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 5.?Analyses of the disc used in Tables 3 and 4 after cleaning and recoating
(only background and Bence-Albee corrections have been made)
Constituent VG-BOO VG-B01 VG-A96 VG-A97 VG-A98 VG-A99 VG-2
"Best"
VG-2
sio2
A12O3
FeO .
MgO .
CaO .
K20 .
Na20
TiO2
P2?5Total
51.68
12.6k
13.37
it.95
9-32
0.82
2.68
1+.11+
0.50
100.10
51.1+6
12.1+6
13.33
U.83
9-29
0.83
2.6U
U.16
0.U8
99.<+8
50.69
14.0U
11.59
5.90
11.18
0.6k
2.1+5
3.0U
0.3U
99.87
J+9-35
12.1+0
11.55
9.1+1
11.18
0.50
2.02
2.59
0.28
99-28
50.50
13.68
11.19
6.62
11.55
0.59
2.32
2.93
0.3*+
99.72
51.20
12.65
13.18
5.02
9.1+3
0.85
2.55
1+.06
0.52
99.1+6
51.1+1
13.98
11.81
6.73
11.08
0.19
2.60
1.88
0.21+
99.92
50.81
11+.06
11.81+
6.71
11.12
0.19
2.62
1.85
0.20
99.1+0
TABLE 6.?Analyses from Table 5 have been normalized to the "best" chemical value
of the internal standard VG-2
Constituent VG-B00 VG-B01 VG-A9-6
Normalizing
VG-A9-8 VG-A99 Factors
FeO .
MgO .
CaO .
K20 .
Na20
TiO2
P2O5
Total
51.08
12.71
13. Uo
1+.91*
9.35
0.82
2.70
U.OT
0.1+2
99. h9
50.86
12.53
13.36
It.82
9.32
0.83
2.66
1+.09
o.i+o
98.87
50.10
11+.12
11.62
5.88
11.22
0.61+
2.1+7
2.99
0.28
99.32
1+8.77
12.1+7
11.58
9.38
11.22
0.50
2.01+
2.55
0.23
98.7^
13.76
11.22
6.60
11.59
0.59
2.3^
2.88
0.28
99.17
50.60
12.72
13.21
5.00
9.h6
0.85
2.57
1+.00
0.1+3
98.81+
0.988
1.006
1.002
0.997
1.001+
1.000
1.008
0.988
0.835
Bence-Albee (1968) correction procedures. The em-
pirical correction factors, used in this procedure,
work especially well when standards with compo-
sitions close to the unknowns are used. VG-2, a
deep sea basaltic glass (analyzed by E. Jarosewich),
appears well suited as a standard for most ocean
ridge basalts and glasses. It is used as the primary
standard for Si, Al, Fe, Mg, Ca, Na, and Ti. Adula-
ria and apatite standards are used respectively for
K and P. For high-alkali and/or high-silica glasses,
a Hawaiian tholeiite standard (VG-A99) or a rhyo-
lite standard (VG-568) are used now as primary
standards.
These refined data are then normalized by the
following method: The VG-2 chip mounted in the
center of each disk, as mentioned above, is analyzed
after the ten unknown basaltic glasses. The probe
value of this VG-2 chip is then compared to the
wet chemical value and factors are established, if
necessary, to correct the probe value of each ele-
ment to the chemical value. The ten unknowns in
the disk are then normalized by applying these
NUMBER 19 27
factors. This procedure corrects for most operational
errors such as long-time probe drift (poor current
bleed-off, because of imperfect carbon coating or
poor contact, etc.). VG-2 has been shown to be
very homogeneous and is well suited for this pur-
pose. Examples of the normalization procedure are
given in Tables 3-6. In Table 3 a run was made on
a disc with a bad carbon coating (porous due to
poor surface adhesion). The oxide sums are sys-
tematically low. Normalizing the VG-2 analysis of
that disc to its wet chemical value produces a set
of normalization factors. Table 4 gives the norma-
lized analyses and the factors used. Recoating the
sample disc produced the analyses in Tables 5 and
6. If an analysis has been performed well then
normalization is no more than 0.01% to 0.02%.
Analyses that sum to less then 98.5 are generally
deleted from the data base and set aside for re-
analysis.
Melson, et al. (1976) compare the glass analyses
of this laboratory to analyses of the same glasses at
the MIT Laboratory (Frey, Bryan, and Thompson,
1974). The comparisons show systematic differences
between the two laboratories. Total iron as FeO is
somewhat higher, while Na2O and MgO are lower
than in the analyses reported by Frey, Bryan, and
Thompson (1974). The Na2O value of the standard
glass VG-2 used by Frey, Bryan, and Thompson is
too low by 0.15 wt. Use of this value in their cor-
rection procedures may be the explanation for
some of these interlaboratory variations. Further
comparisons should help resolve some of the syste-
matic differences.
Homogeneity of Basaltic Glass
Microprobe analyses of abyssal basaltic glasses
demonstrate their homogeneity on the thin section
and outcrop scales. XRF analyses o? similar bulk
material shows considerably more inhomogeneity.
To test the homogeneity of basaltic glass in a single
pillow two thin sections were made of a Juan de
Fuca Ridge sample (Melson, 1969) from palagonite
and glass and from the variolitic zone. Microprobe
analyses were made in eight areas of the two thin
sections as shown in Table 7. The three areas within
the glassy zone compare very favorably to one an-
other. Comparing these to the glass within 100
microns of the palagonite interface shows only so-
dium deviating at the 95% confidence level.
This value of sodium at the palagonite glass inter-
face is just outside the 95% confidence level and
should be studied further. Tentatively, this may
be related to an incipient stage in the alteration of
glass. Comparison of the variolite to glass chemistry
shows a definite loss of iron and magnesium and a
gain of sodium in the variolites relative to glass.
There is no change in potassium so this is inter-
preted as a deuteric alteration of the variolitic
zone.
TABLE 7.?Compositional variations within glassy and variolitic zones
Zone
Within 100 microns
of palagonite-glass
interface
Isolated variolites ....
Connected variolites ...
White variolites
Brown variolites .......
Glass
Glass
Glass
No. of
points SiO A12?3 FeO MgO CaO K2?
0.27
0.26
0.27
0.26
0.28
0.26
0.26
0.27
TiO2
1.96
1.96
1.95
1.84
1.91
1.97
1.98
1.97
P2O5
0.27
0.26
0.25
0.25
0.26
0.26
0.26
0.26
41 49.70 15.53 10.38
19 50.27 15.23 10.46
25 50.86 15.61 10.24
15 49.99 16.31 10.11
21 50.91 16.09 9.62
24 50.28 15.61 10.57
38 50.05 15.68 10.56
32 50.63 15.74 10.59
7.35 11.08 2.93
7.19 10.91 3.05
6.68 11.00 3.21
6.69 10.68 3.26
6.07 10.75 3.31
7.52 11.04 3.04
7.42 11.05 3.04
7.58 11.10 3.05
28 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 8.?Homogeneity of basaltic glasses (mean and 95% confidence interval (2 sd) on ex-
amples from text; numbers in parentheses indicate total number of analyses; each analysis
represents five 10-second point counts, except for USNM 111230, where the 91 analyses are for
single 10-second point counts)
Constituent
Standard glass
VG-2
(77)
usra #111230
(91)
Galapagos
DeSt. 5
(76)
DSDP Site 238
(21)
SiO2
A12O3
FeO .
MgO . .
CaO . ,
Na20 .
K20 ..
TiO2 ,
P2?5 '
Total
50.81 + 0.70
Ik.06 + 0.30
11.8k + 0.31*
6.71 + 0.22
11.12 + 0.30
2.62 + 0.08
0.19 + 0.0^
1.85 + 0.12
0.17 i o.oU
99-37
50.30 ? 1.0U
15.68 + 0.51
10.57 + 0.23
7.50 + 0.51
11.07 + 0.27
3.0U + 0.10
0.26 + 0.05
1.97 + 0.11
0.26 + 0.06
100.65
50.13 ? 0.88
16.2U + 0.5k
9.02 + 0.38
8.U3 + 0.37
12.50 + 0.37
2.20 + 0.08
0.06 + 0.03
1.03 + 0.12
0.07 + 0.02
99.68
U9.1+7 i 0.73
15.Ik + O.Ul
11.15 + 0.17
7.58 + 0.3U
12.61 + 0.17
2.U5 + 0.07
0.07 + 0.03
1.22 + 0.09
0.08 + 0.02
99-77
Analyses of 76 glassy pillow fragments from the
Galapagos Ridge demonstrate the homogeneity of
glasses within a single dredge haul. Table 8 gives
the mean and two standard deviations for the glass
analyses. Comparing the standard deviation for
this dredge against that of VG-2 we find very close
agreement. The increase in 2o- for Al, Mg, and Ca
is partially due to the higher contents of these
oxides in the dredged glasses. Similarly the lower 2a
for K and P are due to lower concentrations. The
extreme homogeneity of the glasses from this dredge
haul, which yielded several hundred pounds of
glassy pillow basalt, is not unusual in the dredges
that have been extensively analyzed by this lab-
oratory (Melson, et al., 1976).
A second example of the homogeneity of glass
in pillow basalts is demonstrated by variations in
chemistry in a 70-meter interval of core from Leg
24, Site 238, DSDP (Melson, et al., 1976). Glass
from each glassy horizon was analyzed and, along
with XRF analyses (Dmitriev, 1974) from the same
core, plotted in Figure 1 as a function of depth.
The glasses are clearly much more homogeneous
than the XRF analyses of the crystalline material.
Fe, Mg, and, to a lesser extent, Ca are depleted
in the crystalline material while K and Na are
enriched. These chemical variations in the crystal-
line material and the concurrent homogeneity of
the glasses again document the superiority of glass
analyses.
In Table 8 the mean and standard deviations of
the Galapagos dredge and DSDP Site 238 are com-
pared to VG-2. The standard deviations are very
close to being only a function of analytical error
and differences in concentration. This indicates that
these analyses reflect single eruptive events and that
on a larger scale glass analyses could be very im-
portant in chemical stratigraphy. Melson, et al.
(1976) present data from this laboratory indicating
the extent to which the chemically homogeneous
groups from one DSDP site or dredge location can
be distinguished and compared to groups within or
between locations. This technique seems quite
promising because of the precision of the analyses
used. A data file of chemically distinct groups of
glass analyses is being built, which will be used in
studying regional differences in basaltic chemistry.
Preliminary data on subaerial glasses indicate a
homogeneity similar to that of abyssal basaltic
glasses. The Hawaiian tholeiite glass standard
(VG-A99) and the rhyolite glass standard (VG-568)
used here have been checked extensively by probe
for homogeneity. Two suites of fractionally crys-
tallized Hawaiian tholeiite glasses are currently be-
ing studied at this lab. Using a least squares liquid
line of descent to compare the glass analyses they
NUMBER 19 29
TiO2
-
-K20
-Na2O
_CaO
* *
4-V
*
*
*
?
* ?
i
*
i
it
1
*
it
k
*
?
/
*
*
*
*
*
?
?
*
?
500
O)
'55 in
MgO
FeO'
AI2O3
SiO2
* ?
*
?
*
*
r ? ??
* *
*
:*?
*
*
?
?
V
1
#
1
*
1
?. *.
**
?k
it
*
it
*
it
?
?
it
m
it
it
1
1
1
1
500 550
Depth(m)
FIGURE 1.?Variation in glass and whole rock chemistry
with depth in a 70-meter interval at DSDP Site 238.
? microprobe analyses of glass
* XRF analyses of whole rocks
appear very homogeneous within the limits imposed
by the precision of the microprobe technique (T. L.
Wright of the U.S. Geological Survey, pers. comm.).
In summary, basaltic glasses often contain vol-
umes which remain unaltered after much of the
remaining rock has undergone some alteration.
Analyzing these separately yields homogeneous re-
sults both within single pillow fragments and within
large single eruptive events. An electron-microprobe
technique has been presented that minimizes many
sources of variations by the inclusion of internal
standards with all unknowns. Using this rapid and
precise technique much more information on the
chemical diversity of the midocean ridges is being
discovered.
Literature Cited
Bence, A. E., and A. L. Albee
1968. Empirical Correction Factors for the Electron Micro-
analyses of Silicates and Oxides. Journal of Geology,
76:382-401.
Corliss, J. B.
1970. Mid-Ocean Ridge Basalts, I: The Origin of Sub-
marine Hydrothermal Solutions; II: Regional Diver-
sity Along the Mid-Atlantic Ridge. Ph.D. disserta-
tion, University of California, San Diego.
Dmitriev, Leonid V.
1974. Petrochemical Study of the Basaltic Basement
of the Mid-Indian Ridge: Leg 24, Djibouti to
Mauritius. Pages 767-779 in L. Musich, editor,
Initial Reports of the Deep-Sea Drilling Project,
24. San Diego: Scripps Institution of Oceanography.
Frey, F. A., W. B. Bryan, and G. Thompson
1974. Atlantic Ocean Floor: Geochemistry and Petrology
of Basalts from Legs 2 and 3 of the Deep-Sea
Drilling Project. Journal of Geophysical Research,
79:5507-5527.
Hart, R.
1973. A Model for Exchange in the Basalt-Sea water Sys-
tem of Oceanic Layer II. Canadian Journal of Earth
Sciences, 10:799-816.
Hart, S. R.
1969. K. Rb, Cs Contents and K/Rb, K/Cs, Ratios of
Fresh and Altered Submarine Basalts. Earth and
Planetary Science Letters, 6:295-303.
Hart, S. R., A. J. Erlank, and E. J. D. Kable
1974. Sea Floor Basalt Alteration: Some Chemical and
Sr Isotopic Effects. Contributions to Mineralogy and
Petrology, 44:219-230.
Hekinian, R.
1971. Chemical and Mineralogical Differences between
Abyssal Hill Basalts and Ridge Tholeiites in the
Eastern Pacific Ocean. Marine Geology, 11:77-91.
Matthews, D. H.
1971. Altered Basalts from Swallow Bank, an Abyssal
30 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
Hill in the NE Atlantic, and from a Nearby Sea-
mount. Philosophical Transactions of the Royal
Society of London, A268:551-571.
Melson, W. G.
1969. Preliminary Results of a Geophysical Study of Por-
tions of the Juan de Fuca Ridge and Blanco Frac-
ture Zone. Coast and Geodetic Survey Technical
Memorandum, 6.
1973. Basaltic Glasses from the Deep Sea Drilling Project,
Chemical Characteristics, Compositions of Alteration
Products, and Fission Track "Ages." Transactions of
the American Geophysical Union, 54:1011-1014.
Melson, W. G., and G. Thompson
1973. Glassy Abyssal Basalts, Atlantic Sea Floor near St.
Paul's Rocks: Petrography and Composition of Sec-
ondary Clay Minerals. Bulletin of the Geological
Society of America, 84:703-716.
Melson, W. G., G. Thompson, and Tj. Van Andel
1968. Volcanism and Metamorphism in the Mid-Atlantic
Ridge, 22 ?N. Journal of Geophysical Research,
73:5925-5941.
Melson, W. G., T. L. Vallier, T. L. Wright, G. Byerly, and
J. Nelen
1976. Chemical Diversity of Abyssal Volcanic Glass
Erupted along Pacific, Atlantic, and Indian Ocean
Sea-Floor Spreading Centers. In G. H. Sutton, M. H.
Manghnani, and R. Moberly, editors, Geophysics of
the Pacific Ocean Basin and Its Margin. Washington,
D.C.: American Geophysical Union.
Moore, J. G.
1965. Petrology of Deep-Sea Basalt near Hawaii. Science,
263:40-52.
1966. Rate of Palagonitization of Submarine Basalt Adja-
cent to Hawaii. United States Geological Survey Pro-
fessional Paper, 550-D:D163-D171.
Moreland, G.
1968. Preparation of Polished Thin Sections. American
Mineralogist, 53:2070-2074.
Muehlenbachs, K., and R. N. Clayton
1972. Oxygen Isotope Studies of Fresh and Weathered
Submarine Basalts. Canadian Journal of Earth Sci-
ences, 9:172-184.
Paster, T. P.
1968. Petrologic Variations within Submarine Basalt Pil-
lows of the South Pacific-Antarctic Ocean. Ph.D.
dissertation, Florida State University, Tallahassee.
Shido, F., A. Miyashiro, and M. Ewing
1974. Compositional Variation in Pillow Lavas from the
Mid-Atlantic Ridge. Marine Geology, 16:177-190.
Thompson, G.
1973. A Geochemical Study of the Low-Temperature In-
teraction of Sea Water and Oceanic Igneous Rocks.
Transactions of the American Geophysical Union,
54:1015-1018.
A Catalog of the Major Element Chemistry
of Abyssal Volcanic Glasses
William G. Melson, Gary R. Byerly, Joseph A. Nelen,
Timothy O'Hearn, Thomas L, Wright, and Tracy Vallier
ABSTRACT
A data set is presented on the major element
chemistry of abyssal volcanic glasses analyzed by
electron microprobe in this laboratory. Information
on the location, depth, age and tectonic setting is
also included.
Introduction
The importance of understanding the chemical
variation of abyssal volcanic rocks has been empha-
sized in a number of recent reports (Engel, Engel,
and Havens, 1965; Kay, Hubbard, and Gast, 1970;
Cann, 1971; and Melson, et al., 1976). Many
attempts have been made in the last dozen years
to relate this chemical variation to regional differ-
ences in the upper mantle, differences in such tec-
tonic parameters as spreading rates, or variation
due to age of the sample and thus length of ex-
posure to weathering and alteration. We present
here a compilation of data on location, tectonic
setting, depth, age, and major element chemistry
for glassy abyssal volcanic rocks analyzed by elec-
tron microprobe in this laboratory. The analytical
technique along with a discussion on the homo-
geneity of abyssal volcanic glasses is presented
William G. Melson, Gary R. Byerly, Joseph A. Nelen, and
Timothy O'Hearn, Department of Mineral Sciences, National
Museum of Natural History, Smithsonian Institution, Wash-
ington, D.C. 20560. Thomas L. Wright, U.S. Geological Sur-
vey, Reston, Virginia 22092. Tracy Vallier, Scripps Institution
of Oceanography, La Jolla, California 92037.
herein by Byerly, et al. Melson, et al. (1976) also
discuss a portion of this data set and have tabu-
lated averages based on a clustering procedure. We
do not include at this time any interpretation of
the data set, but will use it for a series of papers on
regional variations and statistical evaluation of
global patterns in abyssal volcanic rock chemistry.
It is further hoped that other investigators will be
able to use this data set for comparison to other
data sets or statistical tests of newer petrogenetic
models.
The majority of the samples included in this set
are from dredges along the mid-oceanic ridge. A
smaller number of samples are dredged from frac-
ture zones, aseismic ridges, and seamounts. We have
tried to include all glasses that were recovered in
DSDP cores which penetrated sills or pillow basalts.
At present the geographical distribution of sam-
ples is heavily biased towards the Juan de Fuca and
Galapagos regions, which are well represented in
the collections of the National Museum of Natural
History, Smithsonian Institution. The Indian Ocean
spreading system is poorly represented. Long seg-
ments of many spreading systems are not covered.
The data set continues to grow as we receive
samples from other investigators and samples from
new areas are recovered through dredging and the
new International Program for Ocean Drilling.
The catalog* is arranged by ocean, and within
ocean by latitude of the sample location. For DSDP
?This catalog is available on IBM cards or on magnetic
tape and may be purchased from Department of Mineral
Sciences, National Museum of Natural History, Smithsonian
Institution, Washington, D.C. 20560.
32 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
cores the arrangement is stratigraphic from top to
bottom of the hole. In dredges the samples are
arranged in order of increasing FeO* (= total Fe
calculated as FeO) content to aid in rapid scanning
of the data set.
ACKNOWLEDGMENTS.?We are deeply indebted to
the numerous institutions and individuals who
contributed samples for this study and who are
indicated in the "Key to the Catalog." Mr. Eugene
Jarosewich contributed substantially by providing
classical analyses of basaltic glasses that were used
as standards.
Literature Cited
Cann, J. R.
1971. Major Element Variations in Ocean-Floor Basalts.
Philosophical Transactions of the Royal Society 0}
London, A268:495-505.
Engel, A. E., C. G. Engel, and R. G. Havens
1965. Chemical Characteristics of Oceanic Basalts and
Upper Mantle. Bulletin of the Geological Society of
America, 76:719-734.
Kay, R., N. J. Hubbard, and P. W. Gast
1970. Chemical Characteristics and Origins of Oceanic
Ridge Volcanic Rocks. Journal of Geophysical Re-
search, 75:1585-1613.
Melson, W. G., T. L. Vallier, T. L. Wright, G. R. Byerly, and
J. Nelen
1976. Chemical Diversity of Abyssal Volcanic Glass
Erupted Along Pacific, Atlantic, and Indian Ocean
Sea-Floor Spreading Centers. In G. H. Sutton, M. H.
Manghnani, and R. Moberly, editors, Geophysics of
the Pacific Ocean Basin and Its Margin. Washington,
D.C.: American Geophysical Union.
Key to the Catalog
LAT. Latitude of sample
LONG. Longitude of sample
DEPTH Water depth in meters; in the case of dredges, the
greatest depth
AGE Probable age (millions of years) of sample: M =
magnetic anomaly age, S = overlying sediment age,
<10 = samples less than 10 million years old,
that is, younger than magnetic anomaly five
S Probable site of eruption of intrusion: F = frac-
ture zone, M = marginal basin, N = aseismic
ridge, R = spreading rise or ridge
T Type ?f sample: digits = Deep Sea Drilling Proj-
ect site number, D = dredge, C = core, F =
field
E Probable origin: E = eruptive, I = instrusive
FeO* Total iron calculated as ferrous oxide
VG-# Sample number in data file of Department of
Mineral Sciences, National Museum of Natural
Histpry, Smithsonian Institution
SO Source of sample:
= Dr. Fabrizio Aumento, Dalhousie Uni-
versity
|lN = Dr. Tj. van Andel, Oregon State Univer-
sity
= Dr. Wilfred Bryan, Woods Hole Ocean-
ographic Institution
BW = Dr. V. T. Bowen, Woods Hole Oceano-
graphic Institution
CL = Dr. David Clague, Scripps Institution of
Oceanography
CM = Dr. John Campsie, Ocean Study Group,
Copenhagen
CN = Dr. J. R. Cann, University of East Anglia
CR = Dr. Jack Corliss, Oregon State University
DP = Deep Sea Drilling Project of the Scripps
Institution of Oceanography
JH = Dr. Leonard Johnson, U.S. Naval Oceano-
graphic Office
LM = Lamont-Doherty Geological Observatory
MY = Dr. Akiho Miyashiro, SUNY Albany
SC = Scripps Institution of Oceanography (ob-
tained by Dr. Tracy Vallier and Mr.
Richard Nishimori)
SH = Dr. Anatol Sharaskin, Vernadsky Institu-
tion of Geochemistry and Analytical
Chemistry
TH = Dr. Geoffrey Thompson, Woods Hole
Oceanographic Institution
US = National Museum of Natural History,
Smithsonian Institution (formerly of the
United States National Museum)
VG = Dr. Peter Vogt, U. S. Naval Oceano-
graphic Office
NUMBER 19 33
ATLANTIC OCEAN
LAT. LONG. DEPTH AGE S T E SIO2 AL2O3 FEO* MGO CAO NA2O K2C TIO2 P2O5 SUM VG-# SO
30.89S 017.98W 3938 M 21 R 15 E 51.00 14.44 10.52 7.04 12.08 2.65 .09 1.73 .13 99.68 610 DP
28,545 023.68W 4677 M 53 R 19 E 50.99 15.55 9.17 7.48 12.40 2.50 .23 1.27 .09 99.68 298 DP
28.54S 023.68W 4677 M 53 R 19 E 50.65 15.24 9.53 7.91 12.66 2.08 .08 1.26 .08 99.49 417 UP
28.33S 020.94W 4346 M 39 R 14 I 49.97 17.26 8.39 9.51 12.92 1.99 .01 .73 .03 100,81 607 DP
28.33S 020.94W 4346 M 39 R 14 I 50.02 17.62 8.35 9.24 12.88 2.02 .01 .81 .05 101.00 608 DP
27.995 008.02W 4018 S 26 R 18 E 50.14 16.81 8.25 9.59 13.01 1.71 .04 .74 .04 100.33 297 DP
27.99S 008.02W 4018 S 26 R 18 E 50.73 16.88 8.22 9.84 13.33 1.68 .04 .73 .05 101.50 416 DP
27.99S 008.02W 4018 S 26 R 18 E 49.95 17.29 7.91 9.14 13.23 1.76 .00 .69 .04 100.01 611 DP
22.92S 013.51W 31U < 10 R D E 51.03 15.57 10.02 7.25 11.03 3.16 .11 1.83 .14 100.14 208 TH
22.92S 013.51W 31H < 10 R D E 50.60 15.39 10.06 7.21 11.11 2.87 .10 1.79 .14 99.27 207 TH
22.925 013.51W 31H < 10 R D E 49.88 14.88 11.10 7.11 10.72 2.96 .12 2.03 .16 98.96 205 TH
22.92S 013.51W 31H < 10 R D E 51.00 14.87 11.19 7.08 10.69 2.98 .12 2.04 .18 100.15 206 TH
22.28S 012.07W 3660 < 10 R D E 50.70 15.39 10.01 7.30 11.41 3.33 .05 1.69 .11 99.99 194 TH
21.935 011.811* 3660 < 10 R D E 50.92 15.76 8.68 8.53 12.48 2.34 .04 1.14 .09 99.98 191 TH
21.93S Otl.SlW 3660 < 10 R D E 51.10 15.72 8.82 8.30 12.44 2.58 .03 1.15 .03 100.17 193 TH
21.93S 011.81W 3660 < 10 R D E 50.62 15.39 9.45 7.89 11.67 2.52 .07 1.54 .14 99.29 190 TH
21.935 011.81W 3660 < 10 R D E 50.50 14.88 10.49 7.93 10.73 2.92 .10 1.94 .16 99.65 192 TH
21.93S 011.81W 3660 < 10 R D E 50.49 14.84 10.52 7.98 10.60 2.76 ,11 1.87 .14 99.31 189 TH
21.87S 011.85k 3587 < 10 R D E 51.11 15.37 9.34 7.83 12.12 2.66 .06 1.35 .09 99.93 197 TH
21.875 011.85W 3587 < 10 R D E 50.92 15.53 9.44 7.99 11.66 2.46 .07 1.53 .11 99.71 195 TH
21.87S 011.85W 35B7 < 10 R 0 E 50.86 15.36 9.45 7.70 12.08 2.74 .05 1.29 .0/ 99.60 196 TH
21.87S 011.85W 358? < 10 R D E 50.74 14.91 10.53 8.06 10.74 2.83 .07 1.88 ,16 99.92 198 TH
00.48S 020.52W 5760 F D - 48.67 17,09 9.85 7.63 9,78 3.72 .79 1.57 .24 99.34 266 TH
00.485 020.52W 5760 F D - 48.29 17.04 9.88 7.79 9.82 3.65 .69 1.62 .26 99.04 268 TH
00.48S 020.52W 57&0 F D - 48.57 17.17 9.93 7.69 9.75 3.72 .74 1.55 .24 99.36 267 TH
00.48S 020.52W 5760 F D - 48.78 16.88 10.05 7.74 9.62 3.65 .76 1.59 .20 99.27 265 TH
00.485 020.52W 5760 F D - 47.04 17,23 10.18 7.31 10.09 3.82 .94 1.66 .20 98.47 269 TH
00.485 020.52W 5760 F D - 48.86 17.04 10.22 7.84 9.84 3.56 .62 1.57 .17 99.72 271 TH
00.48S 020.52W 5760 F D - 48,77 17.13 10.25 7.73 9.93 3.55 .64 1.55 ,17 99.72 272 TH
00.485 020.52W 5760 - F D - 48.10 16.86 10.36 8.53 9.49 3.56 .62 1.50 .17 99.19 270 TH
00.33N 016.95W 5175 F D E 50.88 14.85 11.27 6.77 10.70 2.92 .11 2.06 .18 99.74 263 TH
00.91N 030.28W 2579 F D E 50.80 16.04 9.28 7.81 11.99 2.41 ,22 1,26 ,10 99.91 398 BW
00.91N 030.28W 2579 F D E 50.88 15.97 9.55 7.88 11.92 2.41 ,22 1.28 .10 100.21 394 BW
00.91N 030.28W 2579 F D E 51.24 15.88 9.55 7.80 11.74 2.47 .21 1.30 .10 100.29 395 BW
00.91N 030.28W 2579 F D E 50.15 16.01 9.59 7.73 11.98 2.41 .22 1.29 .15 99.53 399 BW
00.91N 030.28W 2579 F D E 51.19 16.19 9.63 7.85 11.75 2.39 .24 1.26 .13 100,63 393 BW
34 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
ATLANTIC OCEAN
LAT. LONG, DEPTH
00.91N 030.28W 2579
00.93N 029.37W 2304
00.93N 029.37W 2304
00.93N 029.37W 2304
00.93N 029.37W 2304
00.93N 029.37W 2304
00.93N 029.37W 2304
00.93N 029.37W 2304
00.93N 029.37W 2304
00.93N 029.37W 2304
00.93N 029.37W 2304
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65H 3340
09.60N 040.65W 3340
09.60N 040,65W 3340
09.60N 040.65W 3340
09.60N 040,65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040.65W 3340
09.60N 040,65W 3340
O9.6ON 040.65W 3340
AGE
-
-
-
-
-
-
-
-
-
-
-
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
e 10
< 10
< 10
e 10
c 10
e 10
e 10
c 10
c 10
c 10
: 10
: 10
: 10
c 10
1 10
s
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
T
D
0
D
0
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
0
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
5102
51
50
49
50
50
51
51
50
51
50
50
50
50
51
51
51
50
50
51
51
50
51
51
51
51
50
50
51
51
51
51
51.
50,
51,
50
51,
.06
.81
,89
.23
.55
.22
.10
.73
.57
.61
.96
.61
.77
.83
.57
.02
.89
.90
.17
.29
.70
.01
.25
.60
.47
.83
.88
.66
.32
.08
.31
.57
.82
.44
.84
.46
AL203
15
15
15
15
15
15
15
15
14
15
14
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15,
15,
15
15,
.94
.14
.14
.22
.25
.34
.07
.29
.99
.13
.78
.31
.07
.33
.35
.48
.37
.32
? 36
.02
.19
.38
.20
.29
.11
.22
.64
.23
.35
.17
.36
.19
.37
.30
.24
.26
FEO*
9,
9.
9,
9.
9.
9.
9.
9.
9.
10.
10,
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10,
10.
10.
10.
10.
10.
10.
10.
.64
,51
,55
,63
,67
,71
71
,75
99
39
42
12
18
24
26
28
30
31
31
32
32
38
38
39
40
40
41
41
41
41
45
47
51
51
51
53
MGO
7
6
6
6
6,
6,
6,
6,
6,
5,
4.
6,
7.
7,
7.
7.
7,
7.
7.
6.
.70
.34
.22
.24
.39
.42
.26
.36
.14
.38
.93
.98
.10
.11
.02
,03
.02
,04
.04
.88
7.05
7.
6.
7,
7.
7.
6.
7.
7.
6.
7,
7.
6.
6.
7.
7,
.05
,98
,01
,00
,02
,94
,08
07
97
,06
io
97
92
,06
03
CAO
11
11
11
11
11
11
10
10
11
10
9
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
.88
.27
.07
.24
.33
.14
.85
.88
.34
.44
.44
.78
.84
.79
.68
.89
.90
.82
.79
.77
.76
.75
.69
.83
? 81
.79
.84
.81
.75
.88
.74
.77
.89
.81
.79
.85
NA20
2
2
2
2
2
2
2
2
2
2,
2,
3,
2.
2,
2,
3,
2,
2.
2,
2.
2.
2.
2,
2,
2,
2,
2,
3,
2.
2,
3,
2.
2.
2.
2.
2,
.48
.53
.61
.60
.67
.64
.52
.69
.59
.92
.92
.01
.96
.89
.92
.00
.81
.96
.93
.99
.95
,93
,96
,97
,92
,98
,97
,00
,88
,95
,00
,86
,94
,95
,91
,94
K20
.23
.62
.62
.61
.60
.59
.62
.62
.62
.85
.82
.11
.11
.13
.12
.12
.12
.11
.11
.12
.12
.12
.11
.11
.11
.10
.13
.12
.13
.10
.11
.11
.12
.12
.12
.12
TI02
1
1
1
1
1
1
1
1
1
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
.27
.80
.85
.87
.82
.88
.88
.93
.74
.25
.16
.88
.80
.82
.87
.90
.85
? 80
.85
.82
.78
.82
.89
.85
.85
.83
.90
.91
? 84
.81
.78
? 80
.87
.84
.84
.87
P205 5UM VG-# SO
.12 100.32 396 BW
.20 98.22 401 BW
.21 97.16 410 BW
.21 97.85 409 BW
.18 98,46 404 BW
?23 99.17 402 BW
.21 98.22 407 BW
.18 98.43 403 BW
.24 99.22 405 BW
.27 98.24 406 BW
.29 96.72 408 BW
.16 98.96 212 TH
.14 98.97 229 TH
.15 100,29 238 TH
.15 99.94 240 TH
.16 99.88 213 TH
.14 99.40 246 TH
.14 99.40 230 TH
.13 99.69 236 TH
.14 99,35 227 TH
.14 99.01 234 TH
.14 99.58 226 TH
?14 99.60 242 TH
.17 100.22 233 TH
?14 99,81 245 TH
.17 99.34 247 TH
?14 99,85 214 TH
,13 100,35 232 TH
,15 99,90 239 TH
.14 99.51 248 TH
.11 99.92 231 TH
.13 100,00 243 TH
.16 99.65 225 TH
.18 100.07 241 TH
,14 99,45 244 TH
,16 100.22 235 TH
NUMBER 19 35
ATLANTIC OCEAN
LAT. LONG, DEPTH AGE S T E SIO2 AL2O3 FEO* MGO CAO NA2O K2O TIO2 P2O5 SUM VG-* SO
09.60N 040.65W 3340 < 10 F D E 51.63 15.23 10.55 6.96 10.79 2.94 .11 1.79 .17 100.17 237 TH
09.60N 040.65kv 3340 < 10 F 0 E 50.60 14.97 11.86 7.12 9.37 2.95 .10 1.81 .14 98.92 224 TH
11.05N 043.68W 4750 < 10 F D E 51.39 15.56 10.40 7.79 11.14 2.72 .12 1.64 .08 100.84 255 TH
H.O5N 043,68W 4750 < 10 F D E 51.09 14.81 10.96 6.52 10.91 2.83 .14 2.05 .15 99.46 256 TH
II.O5N 043.68W 4750 < 10 F D E 50.57 14.90 11.14 6.65 10.73 3.01 ,11 2,05 ,17 99,33 264 TH
H.O5N 043.68W 4750 < 10 F D E 50.44 14.95 11.22 6.63 10.84 2.98 .12 2.10 .15 99.43 26l TH
11.05N 043.68W 4750 < 10 F D E 50.29 14.90 11.25 6.66 10.81 2.97 .11 2.16 .18 99.33 262 TH
II.O5N 043.68W 4750 < 10 F D E 50.95 14.76 11.26 6.73 10.82 3.00 .11 2,09 ,15 99.87 259 TH
11.05N 043,68W 4750 < 10 F D E 50,62 14,85 11,28 6.70 10.91 2.94 ,11 2.00 .17 99.58 260 TH
11.05N 043.68W 4750 < 10 F D E 50.90 14.57 11.34 6.53 10.62 2.90 .11 2.04 .16 99.17 254 TH
11.27N 043.65W 4460 < 10 F D E 50.83 15.52 10.37 7.32 11.69 2.78 .09 1.75 .15 100.50 257 TH
11.27N 043,65W 446? < 10 F D E 51.65 15.41 10.39 7.45 11.17 2.88 .08 1.59 .12 100.74 250 TH
11.27N 043.65W 4460 < 10 F D E 51.42 15.44 10.39 7.07 11.63 2.95 .08 1.80 .12 100.90 258 TH
11.27N 043.65W 4460 < 10 F D E 51.19 14.85 10.41 7.21 11.40 2.79 .08 1.70 .13 99.76 252 TH
11.27N 043.65W 4460 < 10 F D E 51.59 15.31 10.43 7.25 10.97 2.97 .07 1.60 .07 100.26 249 TH
U.27N 043.65W 4460 < 10 F D E 51.30 14.89 10.48 7.12 11.37 2.75 .09 1.78 .15 99.93 251 TH
11.27N 043.65W 4460 < 10 F D E 50.95 15.34 10.52 7.62 11.06 2.83 .09 1.57 .14 100.12 253 TH
14.51N 069.34W 4545 S 90 M 150 I 49.72 13.95 11.13 7.33 12.58 1.98 .09 1.20 .08 98.06 628 DP
14.51N 069.34W 4545 S 90 M 150 I 49.19 14.44 11.25 7.32 12.67 1.97 .07 1.22 .10 98.23 629 DP
14.51N 069.34W 4545 S 90 M 150 I 50.42 14.70 10.93 6.88 12.59 1.97 .08 1.25 .08 98.90 631 DP
22.17N 045.25W 3200 < 10 R D E 51.01 14.97 10.02 7.13 12.42 2.53 .13 1.34 .09 99.64 282 5C
22.17N 045.25W 3200 < 10 R D E 51.52 14.93 10.03 7.19 12.22 2.58 .11 1.37 .10 100.05 939 SC
22.17N 045.25W 3200 < 10 R D E 51.01 15.55 10.06 7.37 11.01 2.95 .13 1.69 .15 99.92 940 SC
22.17N 045.25W 3200 < 10 R D E 50.45 15.85 10.08 7.34 10.93 2.90 .16 1.83 .15 99.69 284 SC
22.17N 045.25W 3200 < 10 R D E 50.48 15.49 10.09 7.30 11.09 2.88 .16 1.80 .14 99.43 287 SC
22.17N 045.25W 3200 < 10 R D E 50.39 15.76 10.10 7.17 11.14 3.01 .16 1.73 .16 99.62 283 SC
22.17N 045.25W 3200 < 10 R D E 50.82 15.75 10.14 7.22 11.06 2.88 .14 1.81 .14 99.96 280 SC
22.17N 045.25W 3200 < 10 R D E 50.62 15.48 10.19 7.30 11,42 2.87 .15 1.74 .15 99.92 285 SC
22.17N 045.25W 3200 < 10 R D E 50.52 15.74 10.22 7.20 11.07 2.91 .16 1.77 .15 99.74 279 SC
22.17N 045.25W 3200 < 10 R D E 50.61 15.75 10.24 7.41 11.08 3.06 .15 1.79 .15 100.24 288 SC
22.17N 045.25W 3200 < 10 R D E 50.62 15.56 10.28 7.36 11.22 3.05 .18 1.76 .14 100.17 289 SC
22.17N 045.25W 3200 < 10 R D E 50.73 15.06 10.64 7.05 10.89 2,94 ,17 1,91 .12 99.51 291 SC
22.17N 045.25W 3200 < 10 R D E 50.51 14.89 10.66 7.43 10.63 2.85 .12 1.84 .14 99.07 941 SC
22.17N 045.25W 3200 < 10 R D E 50.83 15.10 11.14 6.80 10.71 3.15 .16 1.9l .16 99.96 286 SC
22.19N 045.28W 3100 < 10 R D E 50.02 16.04 9.80 7.36 11.17 2.84 ,13 1.68 .16 99.20 211 AN
22.24N 045.02W 3100 < 10 R D E 50.56 15.65 10.02 7.73 10.95 2.81 .10 1.66 .14 99.62 934 SC
36 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
ATLANTIC OCEAN
LAT. LONG. DEPTH
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045,02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045.02W 3100
22.24N 045,02W 3100
22.24N 0A5.02W 3100
22.36N 045.20W 3000
22.36N 045.20W 3000
22.36N 045.20W 3000
22.36N 045.20W 3000
22.52N 045.05W 2495
22.52N 045.05W 2495
22.52N 045.05W 2495
22.52N 045,05W 2495
22.52N 045.05W 2495
22.52N 045.05W 2495
22.52N 045.05W 24g5
22.52N 045.05W 2495
22.52N 045.05W 2495
22.52N 045.05W 2495
22.52N 045.05W 2495
22.52N 045.05w
AGE
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
c 10
e 10
e 10
e 10
c 10
c 10
e 10
( 10
e 10
c 10
c 10
i 10
c 10
: 10
: 10
: 10
S
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
T
D
D
D
0
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
0
D
D
D
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
SI02
51
50
50
50
50
50
50
50
50
51
50
50
50
50
50
49
50
50
51
49
50
50
51
50
50
50
50
50
50
50
50
51,
50,
51,
50,
50,
.02
.13
.54
.54
.64
? 81
.22
.35
.88
.09
.51
.83
? 14
.61
.56
? 86
? 14
.19
.27
.81
.70
.44
.14
.75
.41
.61
.47
.80
.75
.55
.68
.36
.75
.09
.61
.47
AL203
15
15
15
15
15
15
15
15
16
15
15
15
15.
15,
15,
15,
15.
15.
15,
15,
15,
15.
15,
15.
16.
16.
15.
15.
15.
15.
15.
15.
15.
15.
15.
15.
.39
.48
.63
.54
.54
.72
.36
.39
.12
.79
.50
.72
.16
.57
.61
,37
.35
.38
,33
,03
,40
.22
,27
,05
,15
,56
,62
,36
,48
,46
,51
,18
,10
,73
62
46
FEO*
10
10
10
10
10
10
10
10
10
10
10
10,
10,
10,
10,
10,
10,
10,
10,
11,
10,
10,
U.
U.
9.
9.
9,
9,
9.
9.
9.
9,
9.
9.
9.
9.
.09
? 10
.11
.11
.11
? 13
.13
.13
.15
.16
.18
.19
.21
.21
.22
.31
.44
.49
,53
,68
,91
,96
,04
,35
,38
,69
,78
,82
,84
,86
,88
,93
,94
,94
95
97
MGO
7
7
7
7
7
6
7
7
7
7
7
7
.82
.75
,76
.52
.57
.97
.67
.47
? 04
.35
.67
.48
7.64
7,
7,
7,
7,
7,
6,
7,
6,
6,
6,
6.
8.
7.
7.
7,
7,
7.
7.
7.
7.
7,
7.
7.
.54
.87
.60
.69
.60
.86
,56
,79
,72
,88
,77
,03
,97
,45
,24
,30
,18
,36
,28
,05
,19
28
42
CAC
10.
10,
10.
10.
11.
10.
10,
10.
11.
11.
10,
U.
10.
11.
11.
11.
U.
10.
11.
9.
11.
10.
10.
10.
11.
11.
11.
11.
11.
11.
11.
11.
11.
11.
11.
11.
)
,87
,91
,95
,82
,10
,97
,88
,87
,45
,13
,84
,04
89
04
18
00
01
89
26
24
09
90
99
88
55
52
60
27
55
53
51
72
66
38
33
39
NA20
2
2
2
2
2
3
2
2
3
2
2
2
2
2
3
2
2
2
3
2
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2,
2,
.93
.90
.87
.98
.90
.07
.89
.89
.00
.95
.79
.92
.91
.90
.07
.79
.80
.91
.03
.85
.13
.12
,14
.07
.73
? 76
.92
.88
.85
.90
.78
.77
.73
.88
.94
.88
K20
.13
.13
.13
.12
.13
? 11
.13
.12
.12
.14
.14
.13
.10
.12
.13
.12
.14
? 14
.14
.10
.15
.14
.14
.14
.09
.09
? 14
.13
.15
.13
,14
.15
.14
.14
.15
.13
TI02
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1,
.70
? 66
.74
.67
.67
.71
.71
.64
.75
.76
.64
.72
? 65
.70
.88
.81
.79
? 84
.76
.69
.87
? 98
.98
.05
.54
.44
.75
.65
.65
.85
.75
.66
.70
.68
.71
.76
P2O5 SUM VG-* SO
.12 100.07 937 SC
.16 99.22 925 SC
,14 99.87 923 SC
.13 99.43 928 SC
.15 99.81 931 SC
?14 99.63 932 SC
,14 99.13 935 SC
.14 99.00 933 SC
.15 100.66 926 SC
.13 100,50 924 SC
.12 99.39 281 SC
.14 100,17 278 SC
,14 98,84 930 SC
.15 99.84 938 SC
.13 100,65 294 SC
,16 99,02 929 SC
.15 99.51 936 SC
.16 99.60 922 SC
.14 100.32 927 SC
.15 98.11 296 SC
,16 100.20 920 AN
.15 99.63 273 AN
,16 100,74 921 AN
,18 100,24 274 AN
.10 99.98 904 AN
.12 100.76 290 AN
?13 99.86 906 AN
.13 99.28 901 AN
,17 99.74 892 AN
.16 99.62 907 AN
,12 99.73 905 AN
,13 100,18 911 AN
,15 99.22 895 AN
,14 100,17 898 AN
,13 99,72 896 AN
,15 99,63 903 AN
NUMBER 19 37
ATLANTIC OCEAN
LAT. LONG. DEPTH AGE S T
22.52N 045.O5h 2495 < 10 R l>
22.52N 045.05W 2495 < 10 R D
22.52N 045.05W 24y5 < 10 R D
22.52N 045.05W 2495 < 10 R 0
22.52N 045.05W 2495 < 10 R D
22.52N 045.05W 2495 < 10 R 0
22.52N 045.05W 2495 < 10 R D
22.52N 045.05W 2495 < 10 R D
22.52N 045.05k 2495 < 10 R D
22.52N 045.05W 2495 < 10 R 0
22.52N 045.05W 24g5 < 10 R D
22.52N 045.05W 2495 < 10 R D
22.52N 045.05W 2495 < 10 R Q
22.52N 045.05W 2495 < 10 R 1)
22.52M 045.05W 2495 < 10 R D
22.52N 045.05W 2495 < 10 R D
22.80N 045.20w 2640 < 10 R D
22.8ON 045.20W 2640 < 10 R 0
22.80N 045.20W 2640 < 10 R D
22.80N 045.20W 2640 < 10 R D
23.07N 045.17W 3255 < 1 R D
23.07N 045.17W 3255 < 1 R D
23.42N 052.03W 5615 M 53 R D
23.42N 052.03W 5615 M 53 R D
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R Q
25.40N 045.30W 3300 < 10 R D
25.40N 045.30W 3300 < 10 R D
E SI02 AL2O3 FEO* MGO CAO NA20 K20 TI02 P205 SUM V6-# SO
E 50.76 15.48 10.03 7.23 11.22 2.95 .13 1.78 .14 99.72 894 AN
E 50.53 15.39 10.05 7.44 11.34 2.89 .13 1.73 .13 99.63 908 AN
E 50.35 15.43 10.05 7.45 11.27 2.81 .10 1.72 .13 99.31 909 AN
E 50.34 15.44 10.12 7.21 11.36 2.92 .13 1.90 .13 99.55 902 AN
E 51.01 15.43 10.15 7.34 11.42 2.85 .14 1.77 .15 100,26 916 AN
E 50.47 15.42 10.16 7.46 11.21 2.84 .12 1.79 .13 99.60 899 AN
E 50.92 15.57 10.18 7.40 11.60 2.92 .14 1.72 .13 100,58 913 AN
E 50.73 15.30 10.20 7.42 11.50 2.82 .12 1.72 .15 99,96 900 AN
E 51.67 15.63 10.22 7.49 11.51 2.96 .13 1.67 .12 101.40 915 AN
E 50.99 15,61 10.23 7,40 11.53 2.91 .15 1,74 ,14 100,70 914 AN
E 51.03 16.16 10.35 7.45 11.36 2.91 .14 1.79 .14 101.33 918 AN
E 51.11 15.31 10.40 7.34 11.71 2.82 .14 1.78 .12 100.73 919 AN
E 50.19 14.95 10.58 7.12 10,84 2.99 .13 1.93 .15 98.88 910 AN
E 50.89 15.24 10.84 7.70 10.96 2.96 .14 1.92 .17 100.82 917 AN
E 50.71 15,11 10,73 7.09 10.94 2.99 .15 2.01 .15 99.88 893 AN
E 50.19 15,24 10,75 7.14 10,76 2.94 .13 1.96 .15 99.26 897 AN
E 50.11 16.46 9,76 7,67 11,02 2,92 ,13 1.75 .12 99.94 293 SC
E 49.89 16.29 9.87 7.45 11.00 2.91 .12 1.68 ,11 99,32 275 SC
E 49.92 15.59 10.55 6.87 11.01 2.95 .17 1.90 .16 99.12 276 SC
E 50.85 15.48 10.66 6.87 11.03 2.91 .14 1.88 .14 99.96 277 SC
E 51.30 14.91 10.48 7.28 10.77 2,96 .15 1.83 .13 99.81 F70 TH
E 52.18 15.25 10.66 7.28 10.83 3.03 .17 1.79 .19 101.38 F71 TH
E 50.36 17,73 8,62 8.86 11.58 2,68 .17 1,11 .13 101.24 F73 TH
E 53.33 15.63 9.75 7.26 11.40 2,68 ,09 1,56 ,16 101,86 F72 TH
E 50,69 16,42 8.49 8.64 11.67 2.66 .06 1.26 .12 100.01 740 LM
E 50.06 16,12 8.64 8.98 11.51 2.66 .05 1.38 .10 99.50 745 LM
E 50.35 16.05 8.75 8.95 11.42 2.67 .09 1.24 .10 99.62 766 LM
E 50.31 15,91 9.23 7.43 11.20 2.82 .08 1.58 .11 98,67 750 LM
E 51.45 16.10 9.26 7.59 11.22 3.11 .11 1.57 .12 100.53 739 LM
E 50,64 16,00 9.29 7.84 11,03 2,84 ,10 1.52 ,14 99,40 760 LM
E 49,83 16.38 9.29 7,88 10.99 2,86 ,12 1,48 ,10 9b.93 764 LM
E 50.51 16.43 9.31 7.76 11.21 2.85 .10 1.64 .13 99.94 741 LM
E 50.74 16.18 9.32 7.43 11.23 2.87 .09 1.55 .15 99.56 746 LM
E 50.53 16.41 9.32 7.84 11.24 2.88 .09 1.63 .13 100.07 748 LM
E 50.45 15,94 9,35 7.60 11.17 2.89 .09 1.54 .13 99.16 743 LM
E 51.72 16.32 9.37 7.61 11.24 2.89 .11 1.56 .15 100.97 735 LM
38 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
ATLANTIC OCEAN
LAT. LONG. DEPTH
25.40N 045,30W 3300
25.40N 045.30W 3300
25.40N 045.30w 3300
25.40N 045.30W 3300
25.4ON 045.30W 3300
25.40N 045.30W 3300
25.40N 045.30w 3300
25.40N 045.30W 3300
25.40N 045.30W 3300
25.40N 045.30W 3300
25.40N 045.30W 3300
25.40N 045.30W 3300
25.40N 045.30W 3300
25.40N 045.30w 3300
25.40N 045.30W 3300
25.40N 045.30W 3300
25.77N 045.16W 4304
28.90N 043.32W -
29.71N 042.66W 2430
29.81N 042.73W 1420
29.86N 042.77W 3200
32.87N 052,22W 46g7
32.87N 052.22W 4697
34.90N 069,17W 5251
34.90N 069,17w 5251
34.90N 069.17W 5251
34.90N 069.17W 5251
34.90N 069.17W 5251
34.90N 069,17W 5251
34.90N 069,17W 5251
36.51N 033.66W 2561
36.71N 033,29W 2598
36.71N 033.291* 2598
36.75N 033.28W 2300
36.77N 033.31W 2561
36.85N 032.97W 2000
AGE
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 10
< 1
< 10
< 10
S 85
S 85
S150
S150
S150
S150
S150
S150
S150
< 10
< 10
< 10
< 10
< 10
< 10
S
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
-
-
R
R
R
R
R
H
R
R
R
R
R
R
R
T
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
10
10
105
105
105
105
105
105
105
D
D
D
D
D
D
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
I
I
I
I
I
I
I
I
I
E
E
E
E
?
E
SI02
51.
50,
50,
50.
50,
51.
51.
50.
51,
51.
51.
50.
51.
51.
51.
50.
51.
48.
50.
51.
50.
49.
50.
50.
50.
50.
50.
50.
51.
50.
51.
50.
50.
50.
50.
51.
,24
,21
,25
,11
,95
,23
,46
,77
,00
29
,72
88
35
39
06
40
32
93
21
04
08
89
71
99
57
46
32
83
63
92
27
55
67
95
84
05
AL2O3
15
16
16
16
15
15
15,
15,
15,
15,
15,
16,
15.
15,
15,
.88
? 13
.24
.40
.61
? 36
.14
.44
.41
.64
.50
.07
.37
.25
.59
15.36
15,
17,
16,
16,
15,
16,
16.
15,
15,
15,
15.
15.
15.
14,
15.
15.
15.
15.
14.
15.
.82
,91
,41
,40
,06
,38
,38
,14
,06
,16
,56
,43
38
95
19
23
00
33
96
36
FE0#
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
10
9
9
10
9
11
9
9
9
9
9
9
9,
9,
9
9,
10,
10,
9,
10,
8,
.41
? 41
.43
.51
.60
.61
.65
.65
? 68
.69
.72
.73
.76
.88
.88
? 36
.25
? 25
.39
.69
.62
.06
.38
.63
.68
.64
.71
.75
.68
.60
.83
.28
.38
.72
.07
.71
MGO
7
8
7
7
7
.65
.17
.84
.92
.45
6.97
6
7
8
7
7
7
7
7
7
7
7
8
7
7
7
7
7
8
8
8
8
8
8,
8
7,
7,
7
7,
7,
8,
.93
.93
? 00
.66
.32
.39
.17
.21
.51
? 22
.83
.39
? 46
.29
.66
.44
.59
.35
.54
.65
.64
.86
.13
.15
.69
.72
.70
.99
.89
.08
CAO
11
11
11
11
11
11
11
11
11
11
11
11
11
11
10
10
11
11
11
10
10
11
12
11
12
12
12
12
12
12
11
11
11
12
12
13
.25
.20
.12
.23
.36
.24
.26
.03
.01
.28
.41
.17
.39
.04
.95
.73
.08
.73
.27
.82
.69
.99
.12
.99
.14
.39
.40
.22
.45
.26
.84
.70
.96
.42
.01
,22
NA20
2
2
2
2
2
2
2
2
2
3
2
2
2
2
2
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
2
2
2
2
2
1
.89
.91
.85
.90
.95
.92
? 91
.83
.93
.00
.88
.89
.94
.87
.99
.80
.95
.56
.94
.65
.92
.45
.39
.82
.89
.91
.87
.88
.90
.89
.18
.19
.27
.17
.15
.87
K20
.10
.10
.12
.11
.10
.10
.07
.10
.10
.11
.08
.11
? 06
.08
.12
? 13
.18
.03
.07
.13
.34
.45
.46
.04
.05
.04
.07
.05
.05
.06
? 20
.18
.17
.14
.17
.14
TI02
1.55
1.51
1.56
1.52
1.52
1.53
1.60
1.51
1.74
1.72
1.53
1.71
1.51
1.51
1.58
1.84
1.57
.88
1.46
1.35
1.93
1.53
1.51
1.00
.99
1.06
.96
.95
1.03
1.02
1.12
1.31
1.31
1.12
1.22
.95
P205
.12
.12
.12
.13
.13
.12
.16
.14
.12
.17
.12
.16
? 12
? 10
.10
.19
.14
.05
.15
.11
.23
.18
.19
.06
.06
,06
,07
.07
.07
.07
.09
.11
.12
.10
.12
.11
SUM
100.09
99.76
99.53
99.83
99.67
99.08
99.18
99.40
99.99
100.56
100.28
100.11
99.67
99.33
99.78
99.03
100.14
99.73
100.36
99.48
100.53
99.37
100.73
99.02
98.98
99.37
99.60
100.04
100.32
98.92
99.41
99.27
99.58
99.94
99.43
99,49
VG-f
742
762
765
737
734
763
747
751
736
749
752
744
738
761
767
753
990
968
F76
F77
F78
299
415
621
622
623
624
625
626
627
008
009
010
006
on
F74
SO
LM
LM
LM
LM
LM
LM
LM
LM
LM
LM
LM
LM
LM
LM
LM
LM
CM
SH
SH
SH
DP
DP
DP
DP
DP
DP
DP
DP
DP
BR
BR
BR
BR
BR
VG
NUMBER 19 39
ATLANTIC OCEAN
LAT. LONG. DEPTH AGE. S T E SIO2 AL2O3 FEO* MGO CAO NA2O K2C TIO2 P2G5 SUM VG-* SO
36.88N 033.64W 1818 S3.3 R 332D E 51.78 14.72 10.70 7.16 11.75 2.19 .20 1.13 .13 99.76 662 DP
36.88N 033.64W 1818 S3.3 R 332D E 51.54 14.70 10.71 7.21 11.74 2.16 .20 1.22 .11 99.59 863 DP
36.88N 033.64W 1806 S3.3 R 332B E 51.54 14.88 9.90 7.71 12.38 2.02 .20 1.18 .10 99.91 839 DP
36.88N 033.64W 1806 S3.3 R 332B E 51.43 14.83 10.00 7.73 12.46 2.04 .17 1.12 .13 99.91 840 DP
36.88N 033.64W 1806 S3.3 K 332B E 51.73 14.91 9.94 7.87 12.37 2.02 .20 1.17 .10 100,31 841 DP
36.88N 033.64W 1806 S3.3 R 3326 ? 50.13 16.30 9.37 9.06 12.30 2.02 .10 .76 .07 100.11 842 DP
36.88N 033.64w 1806 S3.3 R 332B E 50.05 16.37 9.27 8.78 12.27 2.07 .12 .76 .06 99.75 843 DP
36.88N 033.64W 1806 S3.3 R 332B E 49.94 16.65 9.22 9.29 12.49 2.05 .08 .64 .03 100.39 844 DP
36.88N 033.64W 1806 S3.3 R 332B E 49.54 16.47 9.05 8.98 12.24 2.05 .07 .64 .04 99.08 845 DP
36.88N 033,64W 1806 S3.3 R 332B E 49.78 16.78 9.11 8.63 12.44 2.08 .08 .63 .05 99.58 846 DP
36.88N 033.64W 1806 S3.3 R 332B E 49.41 16.83 9.07 8.95 12.56 2.03 ,06 .66 .06 99.63 847 DP
36.88N 033.64W 1806 S3.3 R 332B E 49.52 16.50 8.97 8.82 12.18 2.07 ,06 .65 .05 98.82 848 DP
36.88N 033.64W 1806 S3,3 R 332B E 49.42 16.52 9.14 9.20 12.36 2.01 ,06 .63 .05 99.39 849 OP
36.88N 033,64W 1806 S3.3 R 332B E 50.60 15.96 10.07 8.15 11.76 2.35 ,07 ,90 .06 99.92 850 DP
36.88N 033.64W 1806 S3.3 R 332B E 50.56 16.09 10.03 7,87 12,02 2.41 .08 .90 ,07 100.03 851 DP
36.88N 033.64W 1806 S3.3 R 332B E 51.07 16.31 9.92 7.93 11.60 2.41 .07 .89 ,06 100.26 852 DP
36.88N 033,64W 1806 S3.3 R 332B E 50.32 15.81 10.18 7.86 11.63 2.32 .08 .89 .06 99.15 853 DP
36.88N 033.64W 1806 S3.3 R 332B E 50.36 16,20 9.98 7.95 11,81 2.35 .08 .87 .07 99.67 854 DP
36.88N 033,64W 1806 S3.3 R 332B E 50.51 15.98 10.00 8.07 11.91 2.27 .06 .90 .06 99.76 856 DP
36.88N 033,64W 1806 S3.3 R 332B E 50.70 16.12 10.05 7.87 11.67 2.32 ,07 ,86 ,04 99.70 857 DP
36.88N 033,64W 1806 S3.3 K 332B E 50.71 16.23 10.04 7.91 11.78 2.31 .08 .91 .06 100.03 855 DP
36.88N 033.64W 1806 S3.3 R 332B E 50.02 15.55 8.81 8.80 13.92 1.89 .06 .68 .03 99.76 858 DP
36.88N 033.64W 1806 S3.3 R 332B E 49.31 15.83 8.68 8.88 13.89 1.87 ,06 .67 .06 99.25 859 DP
36.88N 033.64W 1806 S3.3 R 332B E 49.91 15.93 8.74 8.42 13.73 1.93 .09 .66 .04 99.45 860 DP
36.88N 033.64W 1818 S3.3 R 332A E 51.34 14.78 9.71 7.57 12.59 2.08 ,16 1.00 ,10 99,33 829 DP
36.88N 033,64W 1818 S3.3 R 332A E 51.21 14.86 9.86 7.67 12.39 2.07 ,16 1.06 .11 99.39 830 DP
36.88N 033.64W 1818 S3.3 R 332A E 51.81 14.60 10.72 6.67 11.44 2.27 .18 1.16 .11 98.96 831 DP
36.88N 033.64W 1818 S3.3 R 332A E 52.01 14.56 11.17 6.72 11.38 2.32 .20 1.22 .11 99.69 832 DP
36.88N 033.64W 1818 S3.3 R 332A E 51.14 14.70 10.62 7.35 11.87 2.08 .23 1.22 ,13 99,34 833 DP
36.88N 033,64W 1818 S3,3 R 332A E 50,94 14,93 10,61 7.56 11.93 2.11 .22 1.26 .14 99.70 634 DP
36.88N 033.64W 1818 S3.3 R 332A E 51.13 14.76 10.61 7.59 11.95 2.07 .22 1.28 .11 99.72 835 DP
36.88N 033.64W 1818 S3.3 R 332A E 51.18 14.86 10.58 7.33 11.90 2.14 .21 1.23 .13 99.56 836 DP
36.88N 033,64W 1818 S3.3 R 332A E 51.67 14.66 10,48 7.47 11.97 2.12 .17 1,13 .10 99.77 837 DP
36.88N 033.64W 1818 S3.3 R 332A E 50.99 14.42 11.25 7.09 11.59 2,20 .20 1.23 .10 99.07 838 DP
37.04N 034.41W 2632 S 10 R 334 E 52.20 14.44 9.9l 7.99 12.70 1.80 .08 .85 .07 100.04 825 DP
37.04N 034,41W 2632 S 10 R 334 E 52.07 14.45 9.97 8.06 12.69 1.83 .09 .83 .07 100,06 826 DP
40 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
ATLANTIC OCEAN
LAT. LONG. DEPTH AGE S T E SIO2 AL2O3 FEO# MGO CAO NA20 K20 TIO2 P205 SUM VG-# 50
37.04N 034.41W 2632 S 10 R 334 E 51.66 14.62 10.03 7.76 12.66 1.79 .09 .85 .08 99.54 827 DP
37.04N 034.41W 2632 S 10 R 334 E 52.17 14.62 9.52 7.82 12.82 1.80 .08 .78 .06 99.67 828 DP
37.30N 035.20W 3198 S 11 R 335 E 50.69 16.28 9.59 6.66 12.12 2.57 ,17 1.17 .09 99.34 800 DP
37.30N 035.20w 3198 S 11 R 335 E 50.35 15.59 9.38 7.96 11.68 2.41 .16 1.12 .10 98.75 801 DP
37.30N 035.20W 3198 S 11 R 335 E 50.11 15.45 9.52 8.14 11.86 2.36 .17 1.14 ,09 98.84 807 DP
37.30N 035.20W 3198 S 11 R 335 E 49.93 15.49 9.44 8.20 11.77 2.38 .16 1.18 .08 98.63 803 DP
37.30N 035.20W 3198 S 11 R 335 E 50.37 15.62 9.44 8.05 11.84 2.44 .16 1.18 .09 99.19 808 DP
37.30N 035.20W 3I98 S 11 R 335 E 50.76 15.71 9.33 8.06 11.78 2.42 .17 1.15 .08 99.46 804 DP
37.30N 035.20W 3198 S 11 R 335 E 51.24 15.47 9.41 7.78 11.84 2.39 .16 1.17 .11 99.57 805 DP
37.30N O35.20W 3198 5 11 R 335 E 50.52 15.59 9.41 8.13 11.77 2.37 .16 1.12 .10 99.17 809 DP
37.30N 035.2OW 3198 S 11 R 335 E 50,32 15,53 9.41 8.13 11,63 2,41 ,19 1.16 .09 98.87 806 DP
37.30N 035.20W 3198 S 11 R 335 E 50.40 15.72 9.47 7.86 11.81 2.41 ,16 1.13 .10 99.06 811 DP
37.30N 035.20W 3198 S 11 R 335 E 51.05 15.94 9.37 7.71 11.91 2.44 .16 1.10 .10 99.78 812 DP
37.30N 035.20w 3198 S 11 R 335 E 50.33 15.77 9.34 8,17 12,03 2,35 .16 1.13 .09 99.37 813 DP
37.30N 035.20W 3198 S 11 R 335 E 50.47 15.66 9.34 7.85 11.83 2.41 .16 1.10 .09 98.91 814 DP
37.30N 035.20W 3198 S 11 R 335 E 50.90 15.92 9.26 7.68 11.90 2.38 .16 1.08 .09 99.37 815 DP
37.30N 035.20W 3198 S 11 R 335 E 50.82 15.66 9.36 7.96 12.00 2.37 .15 1.13 .09 99.54 816 DP
37.30N 035.20W 3198 S 11 R 335 E 50.90 15.74 9.36 7.91 11.91 2.42 .15 1.14 .11 99.64 817 DP
37.30N 035.20W 3198 S 11 R 335 E 51.05 15.59 9.40 8.04 12.01 2.41 .15 1.18 .09 99.92 818 DP
37.30N 035.20W 3198 S 11 R 335 E 50.49 15.50 9.34 7.90 11.95 2.36 .16 1.09 .09 98.88 819 DP
37.30N 035.20W 3198 S 11 R 335 E 50.72 15.77 9.33 8.05 12.02 2.38 .14 1.12 .09 99.62 820 DP
37.30N 035.20W 3198 S 11 R 335 E 50.69 15.78 9.47 8.17 12.03 2.41 .16 1.13 .09 99.93 821 DP
37.30N 035.2OW 3198 5 11 R 335 E 49.92 15.78 9.47 8.10 11.99 2.38 ,17 1,14 .09 99.04 822 DP
37.30N 035.20W 3198 5 11 R 335 E 50.45 15.77 9.51 8.10 12.04 2.36 .16 1.13 .09 99.61 823 DP
37.30N 035.20W 3198 S 11 R 335 E 50.37 15.79 9.19 7.82 11.86 2.41 .16 1.10 .07 98.77 824 DP
40.42N 029.54W 2780 < 1 R D E 51.97 14.28 11.57 7.02 11.67 2.12 .07 1.25 .09 100.04 F80 SH
40.55N 029.21W 2780 < 10 R D E 52.29 15.06 8.97 8.14 13.19 1.81 .04 .74 .07 100.31 F79 SH
42.96N 029.20W 3967 < 10 R D E 50.41 15.64 7.95 9.09 13.35 2.05 .28 .92 ,11 99.80 203 TH
42.96N 029.20W 3967 < 10 R D E 50.73 15.61 7.97 9.34 13.29 1.94 .24 .92 .10 100.14 202 TH
42.96N 029.20W 3967 < 10 R D E 51.25 15.94 8.59 8.02 13.04 2.06 ,27 ,99 ,11 100.27 204 TH
42.96N 029.20W 3323 < 10 R D E 51.09 15.82 8.31 7.18 12.25 2.48 .49 1.37 .15 99.14 199 TH
42.96N 029.20W 3323 < 10 R D E 51.09 15.72 8.53 7.22 12.09 2.51 .50 1.43 .17 99.26 201 TH
42.96N 029.20W 3323 < 10 R D E 51.77 15.53 8.87 6.77 11.29 2.66 .54 1.57 .18 99.18 200 TH
45.12N 028.14W - < 10 R D E 51.23 15.43 9.80 7.97 11.57 2.37 .25 1.36 .11 100.09 313 AM
45.12N 028.33W - < 10 R D E 51.13 15.23 12.59 8.00 8.46 2.37 .21 1.31 .12 99.42 314 AM
45.22N 028.OOW 16&0 < 10 R D E 51.53 15.27 9.45 8.47 11.73 2.24 .21 1.20 .12 100.22 312 AM
NUMBER 19 41
ATLANTIC OCEAN
LAT. LONG. DEPTH
45.33N 028,03^ 0980
45.33N 028,03W 0980
45.33N 028,03W 0980
45.33N 028.03W 0980
45.62N 027.72W 1300
48.54N 028.04W 2434
49.81N 028.65W 3404
52.67N 034.94W 3477
52.67N 034,94W 3477
52.67N 034.94W 3477
52.67N 034.94w 3477
52.67N 034,94W 3477
52.67N 034.94W 3477
52.67N 034,94W 3477
52.67N 034.94W 3477
52.67N 034.94W 3477
52.67N 034.94W 3477
52.67N 034.94W 3477
52.67N 034.94W 3477
52.67N 034.94W 3477
53.07N 035.03W 1702
53.19N 035.08W 2708
70.17N 015.26W 1281
AGE
< 10
< 10
< 10
< 10
< 10
< 10
< 10
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
< 1
s
R
R
R
R
R
R
R
F
F
F
F
F
F
F
F
F
F
F
F
F
S
S
R
T
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
-
-
E
SI02
51.42
51.13
51.11
51.63
51.18
50.88
51.21
50.90
50.56
51.51
51.10
51.76
50.90
49.60
50.72
49.49
49.38
49.26
50.99
51.09
50.71
51.09
51,10
AL203
15.84
15.82
15.59
15.08
14.83
15.28
15.36
16.29
14.96
14.71
14.89
14,51
15.04
15.58
14.54
15.12
15.07
15.05
14,84
14,93
14.86
15.13
14.71
FEO*
8,79
9,06
9.42
10.09
10.49
9.73
9.46
9.68
10.95
10.97
11.00
11.00
11.03
11.09
11.20
11.25
11.35
11.43
12.71
12.89
10.85
9.53
10.03
MGO
7.82
7.77
7.76
7.10
7.21
7.37
8.38
7.76
7.63
7.66
7.53
7.77
7.77
7.23
7.60
6.65
6.70
7.17
7.60
7.69
8.29
8.66
8.00
CAO
11
11
11
11
11
12
11
11
11
11
11
11
12
10
12
10
10
10
10
10
11
12
12
.66
.90
.31
.21
.15
.44
.38
.88
.58
.65
.89
.82
.03
.55
.01
.40
.38
.34
.14
.12
.89
.90
.97
NA20
2.46
2.37
2.51
2.49
2.47
2.69
2.71
2.40
2.15
2.26
2.26
2.25
2.19
2.96
2.19
2.97
2.96
3.02
2.23
2.17
2.17
2.05
1.72
K2C
.31
.26
.27
.26
.12
.20
.07
.22
.07
.08
.05
.06
.07
.27
.07
.36
.35
.30
.06
.04
? 05
.03
.05
TI02
1.22
1.27
1.32
1.50
1.59
1.27
1.39
1.38
1.23
1.32
1.28
1.33
1.32
2.06
1.36
2.18
2.20
2.11
1.29
1.25
1.20
.95
.78
P2O5
.08
.11
.12
.14
.10
.11
.09
.13
,08
.09
.13
.09
.10
.21
.10
.24
.23
.18
.08
.07
? 08
.06
,06
SUM
99,60
99,69
99.41
99.50
99.14
99.97
100.05
100.64
99.21
100,25
100,13
100.59
100.45
99.55
99.79
98.66
98.62
98.86
99.94
100.25
100.10
100.40
99.42
VG-#
309
307
310
305
308
966
965
397
367
F88
F87
F89
411
366
362
363
364
365
330
331
964
963
962
SO
AM
AM
AM
AM
AM
CM
CM
JH
JH
JH
JH
JH
JH
JH
JH
JH
JH
JH
JH
JH
CM
CM
CM
INDIAN
LAT.
59.26S
59.26S
59.26S
59.26S
59.26S
56.40S
56.40S
53.54S
20.15S
OCEAN
LONG,
104,49E
104,49E
104,49E
104,49E
104,49E
110.HE
110.11E
109.95E
067,62E
DEPTH
4554
4554
4554
4554
4554
4163
4163
3572
3400
AGE
S
S
S
S
S
S
S
M
<
38
38
38
38
38
25
25
13
10
S
R
R
R
R
R
R
R
R
R
T
267
267
267
267
267
266
266
265
D
E
I
I
I
I
I
E
E
E
E
SI02
50.30
50.13
49.38
50,29
50.51
51.12
50.78
50.65
49.16
AL203
15.04
14.92
15.12
14.80
15.00
14.03
14.14
17,13
17,28
FEO*
9.33
9.41
9.31
9.38
9.30
11.41
11.39
8.25
8.66
MGO
7.60
7,60
7.95
7.62
7.57
7.23
6.99
8.03
8.64
CAO
11.97
12.12
12.12
12,16
12.17
10.24
10.34
10.59
12.24
NA20
2.54
2.55
2.58
2.50
2.52
2.97
2.91
3.28
2.26
K20
.10
.11
.12
.12
.13
.27
.24
.60
.06
TI02
1.29
1.33
1.35
1.27
1.33
2.19
2.21
1.60
.77
P205
.10
.09
.10
.11
.10
.19
.21
.21
.06
SUM
98,27
96.26
98.03
98,25
98.63
99.65
99.21
100.34
99.13
VG-#
712
713
714
715
716
710
711
709
756
SO
DP
DP
DP
DP
DP
DP
DP
DP
LM
42 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
INDIAN OCEAN
LAT. LONG. DEPTH AGE S T E SI02 AL2O3 FEO* MGO CAO NA2O K20 TI02 P205 SUM VG-* SO
20.15S 067.62E 3400 < 10 R D E 51.51 14.93 10.36 7.04 10.95 2.78 .10 1.64 .12 99.43 759 LM
20.15S 067.62E 3400 < 10 R D E 51.57 14.80 10.47 6.93 11.13 2.77 .10 1.71 .12 99.60 755 LM
20.15S 067.62E 3400 < 10 R D E 51.96 14.71 10.58 6.98 11.12 2.67 .10 1.62 .12 99.86 758 LM
20.15S 06?.62E 3400 < 10 R D E 51.15 14.48 10.65 7.07 11.39 2.70 .10 1.74 .16 99.44 757 LM
19.19S 099.30E 6240 5100 R 212 E 51.33 15.60 7.86 8.97 13.48 1.42 .05 .61 .03 99.35 649 DP
11.15S 070.53E 2845 S 30 R 238 E 50.47 14.80 10.31 7.88 13.76 2.04 .04 .95 .06 100,31 683 DP
H.15S 070.53E 2845 S 30 R 238 E 49.72 14.80 10.17 7.83 13.83 2.09 .06 .91 .05 99.46 684 DP
11.15S 070.53E 2845 S 30 R 238 E 50.17 14.49 11.74 6.88 12.64 2.44 .08 1.28 .08 99.80 685 DP
11.15S 070.53E 2845 S 30 R 238 E 49.29 15.19 11.19 7.47 12.59 2.51 .06 1.23 .09 99.62 686 DP
11.15S 070.53E 2845 S 30 R 238 E 49.44 15.29 11.20 7.60 12.76 2,51 .08 1.19 .08 100.15 687 DP
11.15S 070,53E 2845 5 30 R 238 E 49,81 15.27 11.08 7.50 12.69 2.46 .05 1,27 .07 100.20 688 DP
11.155 070.53E 2845 S 30 R 238 E 49.51 15.22 11.08 7.43 12.58 2.44 .06 1.25 .08 99.65 689 DP
11.155 070.53E 2845 S 30 R 238 E 49.14 14.68 11.14 7.57 12.69 2.48 .08 1.19 .06 99.03 690 DP
11.15S 070,53E 2845 S 30 R 238 E 49.15 15.07 11.03 7.16 12.54 2.44 .05 1.23 .06 98.73 691 DP
11.155 070.53E 2845 S 30 R 238 E 49.40 15.39 11.18 7.60 12.61 2.49 .07 1.16 .10 100.00 692 DP
11.15S 070.53E 2845 S 30 R 238 E 49.62 15.26 10.98 7.72 12.66 2.47 .07 1.28 .08 100.14 693 DP
11.15S 070.53E 2845 S 30 R 238 E 49.57 15.12 11.16 7.55 12.49 2.43 .09 1.16 .07 99.64 694 DP
11.15S 070.53E 284b S 30 R 238 E 49.69 15.20 11.14 7.75 12.65 2.41 .07 1.20 .08 100.19 695 DP
11.15S 070.53E 2845 S 30 R 238 E 49.48 15.25 11.15 7.93 12.69 2.42 .06 1.25 .08 100.31 696 DP
11.15S 070.53E 2845 S 30 R 238 E 48.78 15.01 11.04 7.44 12,65 2.46 .07 1.24 .08 98.77 697 DP
11.15S 070.53E 2845 S 30 R 238 E 49.45 15.25 11.18 7.35 12.60 2.38 .08 1.22 .08 99.59 698 DP
11.15S 070.53E 2845 S 30 R 238 E 49.34 14.98 11.03 7,53 12.39 2.45 .05 1.16 .09 99.02 699 DP
11.15S 070.53E 2845 S 30 R 238 E 49.47 14.92 11.11 7.59 12.71 2.45 .04 1.20 .09 99.58 700 DP
U.15S 070.53E 2845 S 30 R 238 E 48.85 15.39 11.21 7.85 12.71 2.47 .08 1.28 .07 99.91 701 DP
11.15S 070.53E 2845 S 30 R 238 E 50.41 14.83 11.22 7.77 12.53 2.38 .07 1.19 .10 100.50 702 DP
11.15S 070.53E 2845 S 30 R 238 E 49.83 15.50 11.18 7.59 12.54 2.46 .06 1.21 .08 100.45 703 DP
11.15S 070.53E 2845 S 30 R 238 E 49.13 14,82 11.31 7.58 12.55 2.44 ,09 1,33 ,07 99,32 704 DP
11,15S 070.53E 2845 S 30 R 238 E 49.87 15,09 11,18 7,68 12,63 2,48 ,06 1.23 .05 100.27 705 DP
11.15S O7O.53E 2845 S 30 R 238 E 49.70 15.17 11.28 7.51 12.59 2.51 .08 1.23 ,07 100,14 706 DP
10.22S O93.9IE 5611 M 57 R 213 E 49.97 16.14 9.92 8.05 12.14 2.44 .08 1.08 .08 99.90 302 DP
10.22S O93.9IE 5611 M 57 R 213 E 49.66 16.00 9.83 8.38 12.25 2.42 ,06 1.08 .09 99.77 652 DP
10.22S 093,91E 5611 M 57 R 213 E 49.60 15.93 9,82 8.19 12.37 2.39 .05 1.00 .10 99.45 653 DP
10.22S 093.91E 5611 M 57 R 213 E 50.06 15.93 9.94 7.98 12.32 2.42 .06 1.08 .09 99.88 650 DP
10.22S 093.91E 5611 M 57 R 213 E 49,83 15.98 9.9l 8.38 12.25 2.45 .07 1.06 .10 100.03 651 DP
08.13S 086.80E 5319 M 60 N 215 E 50.07 16.60 7.97 6.77 10.81 2.90 .99 1.73 .25 98.09 413 DP
NUMBER 19 43
INDIAN OCEAN
LAT. LONG. DEPTH AGE S T E SIO2 AL2O3 FEO* MGO CAO NA2O K2O TIO2 P2O5 SUM VG-# SO
08.135 086.80E 5319 M 60 N 215 E 50.71 17.02 7.97 7.20 10.50 3.06 .90 1.69 .26 99.31 662 UP
08.13S 086.80E 5319 M 60 N 215 E 50.37 17.06 7.99 7.13 10.51 3.02 .89 1.64 .28 98.89 660 DP
08.13S 086.80E 5319 M 60 N 215 E 50.86 16.92 8.02 7.17 10.60 3.00 .90 1.64 .26 99.37 664 DP
08.13S 086.80E 5319 M 60 N 215 E 50.47 16.85 8.03 7.24 10.49 3.02 .95 1.68 .27 99.00 665 DP
08.13S 086.80E 5319 M 60 N 215 E 51.27 16.56 8.09 6.86 10.44 3.08 .91 1.66 .24 99.11 663 DP
08.13S 086.80E 5319 H 60 N 215 E 50.35 17.13 8.10 7.13 10.76 3.05 .91 1.75 .29 99.47 658 DP
08.13S 086.80E 5319 M 60 N 215 E 50.95 17.02 8.11 7.02 10.64 3.06 ,90 1.58 .24 99.52 661 DP
08.135 086.80E 5319 M 60 N 215 E 49.98 17.05 8.12 6.98 10.59 3.02 .89 1.68 .27 98.58 656 DP
08.13S 086.80E 5319 M 60 N 215 E 50.85 16.79 8.12 7.03 10.67 3.03 .96 1.69 .25 99.39 659 DP
08.135 086.80E 5319 M 60 N 215 E 51.04 17.05 8.14 7.25 10,67 3.07 .94 1.66 ,26 100,08 655 DP
08,135 086,80E 5319 M 60 N 215 E 51,26 17,14 8,17 6,86 10,65 2,94 1.10 1,74 .25 100.11 300 DP
08.13S 086.80E 5319 M 60 N 215 E 51.04 16.86 8.21 6.83 10.66 3.07 1.01 1.76 .26 99,70 301 DP
08.13S 086.80E 5319 M 60 N 215 E 51.07 16.77 8.32 6.94 10.73 3.01 .98 1.76 .25 99.83 414 DP
08.13S 086.80E 5319 M 60 N 215 E 50.49 16.79 8.33 6.83 10.67 3.05 .96 1.73 .27 99,12 657 DP
01.68S 052.65E 4504 M 68 R 236 E 53.31 14.41 10.03 7.68 12.38 1.63 .06 .59 .03 100.12 678 DP
01.68S 052,65E 4504 M 68 R 236 E 53.62 14.55 10.02 8.24 12.43 1.63 ,07 .65 .05 101.26 679 DP
01.685 052.65E 4504 M 68 R 236 E 53.74 14.56 9.77 7.71 12.43 1.66 .05 .62 .04 100.58 680 DP
01.68S 052.65E 4504 M 68 R 236 E 53.38 14.51 10.00 8.04 12.40 1.67 .06 .61 .04 100,71 681 DP
01.685 052.65E 4504 M 68 R 236 E 52.84 14.13 9.82 7.34 12,24 1.66 .06 .59 .04 98.72 682 DP
05.05N 062.08E 3400 < 10 R D E 50.21 15.57 10.31 6.95 10.66 3.22 ,19 1.64 .16 98.91 F85 SH
05.35N 068.68E 4100 - R D E 49.98 15.61 10.84 7.38 10.70 3.03 .04 1.58 .14 99.30 F84 SH
05.37N 068.47E 1900 - R D E 51.23 15.76 8.61 8.05 12.21 2.24 .12 1.06 .11 99.39 F81 SH
05.46N 061.84E 2820 < 10 R D E 49.58 16.52 9.64 7.75 10,76 2.97 .10 1.36 .11 98.79 F86 CN
05.52N 068.52E 5200 - R D E 51.31 14.99 9.27 6.78 11.64 2.74 .20 1.39 .10 98.42 F82 SH
06.52N 070.98E 4036 S 51 N 220 E 52.11 13.98 12.92 6.15 10,44 2,19 .24 1.25 .11 99.39 666 DP
06.52N 070.98E 4036 S 51 N 220 E 52.72 13.62 12.90 6.00 10.52 2.20 ,24 1,25 ,15 99,60 667 DP
07.97N 068.41E 4650 S 46 R 221 E 52.32 13.78 12.23 6.67 11.20 2.17 .08 1.13 .09 99.67 668 DP
07.97N 068.41E 4650 S 46 R 221 E 52.18 13.93 12.21 6.66 11.02 2.18 .08 1.12 .10 99.48 669 DP
II.89N 048,25E 2152 S 25 R 231 E 49.96 15.09 10.81 8.72 11.58 2.25 .06 1.12 .07 99.66 670 DP
H.89N 048.25E 2152 S 25 R 231 E 49.76 14.92 10.83 8.63 11.56 2.30 .05 1.14 .09 99,28 671 DP
II.89N 048.25E 2152 S 25 R 231 E 50.32 15.22 10.87 8.26 11.76 2.38 .07 1.20 .07 100,15 672 DP
II.89N 048,25E 2152 S 25 R 231 E 50.71 15.07 10.71 8.53 11.75 2.35 .06 1.20 .08 100.46 673 DP
II.89N 048.25E 2152 S 25 R 231 E 50.70 15.06 10.76 8.25 11.53 2.33 .08 1.20 .08 99.99 674 DP
44 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
PACIFIC OCEAN
LAT. LONG. DEPTH AGE S T E SIO2 A12O3 FEO* MGO CAO NA2O K20 TIO2 P2O5 SUM VG-# SO
56.56S 160.07E 3698 S 30 R 278 E 49.73 16.19 8.39 8.01 12.96 2.22 .09 1.02 .07 98.68 717 DP
56.56S 160.07E 36g8 S 30 R 278 E 49.60 15.73 8.46 8.57 12.95 2,22 .09 .99 .11 98.72 718 DP
56.565 160.07E 3698 S 30 R 278 E 49.88 15.96 8.43 8.48 12.91 2.18 .08 1.06 .08 99.06 719 DP
56.56S 160.07E 3698 S 30 R 278 E 49.33 16.13 8.31 8.52 13.07 2.18 .11 1.09 .10 98.84 720 DP
56.565 160.07E 3698 S 30 R 278 E 50.18 15.88 8,40 8,21 13.10 2.26 .08 1.01 ,07 99.19 721 DP
56.56S 160.07E 3698 S 30 R 278 E 50.00 16.03 8.48 8.22 13.13 2.26 .08 1.04 .08 99.32 722 DP
56.565 160,07E 36g8 S 30 R 278 E 50.34 16.14 8.42 8.22 12.91 2.20 .07 .99 .08 99.37 723 DP
56.565 160.07E 3698 S 30 R 278 E 49.74 16.09 8.40 8.08 13.07 2.24 .07 1.03 ,08 98.80 724 DP
56.56S 160,07E 36g8 S 30 R 278 E 4g.52 16.03 8.50 8.70 13.01 2.19 .05 1.07 ,08 99.15 725 DP
56.565 160.07E 36g8 S 30 R 278 E 49.71 16.24 8.27 8.27 12.91 2.26 .13 1.05 .07 98.91 726 DP
56.56S 160.07E 3698 S 30 R 278 E 50.71 15.86 8.55 8.28 13.00 2.20 .07 .98 .10 99.75 727 DP
42.25S 143.40E 4207 S 40 R 282 E 49.79 16.83 8.91 7.85 11.53 3.06 .10 1.37 .12 99.56 729 DP
42.255 143.40E 4207 S 40 R 282 E 48.81 16.89 8.95 7.75 11.63 3.08 .10 1.49 .12 98.82 731 DP
31,005 113.12W 2453 < 10 R D E 50.51 15.08 9.98 7.38 12.15 2.97 .13 1.53 .12 99.85 796 CR
31.005 113.12W 2453 < 10 R D E 50.53 15.05 10.02 7.28 12.16 2.94 .12 1.64 .12 99.86 798 CR
31.00S 113.12W 2453 < 10 R D E 50.54 14.92 10.08 7.26 12.18 2.98 .13 1.55 .11 99.75 795 CR
31,005 113.12W 2453 < 10 R D E 50.06 15.20 10.08 6.91 11.80 3.06 .22 1.73 .16 99.22 869 CR
31.00S 113,12W 2453 < 10 R D E 50.29 14,93 10.12 7.00 11.92 3.12 .19 1.74 .17 99.48 799 CR
31.005 113.12W 2453 < 10 R D E 50.70 15.28 10.12 6,87 11,82 3.00 .21 1.75 .16 99.91 866 CR
31.00S 113.12W 2453 < 10 R D E 50.20 14.97 10.17 7.05 11.90 3.00 .20 1.76 .14 99.39 864 CR
31.00S 113,12W 2453 < 10 R D E 50,79 14,66 10,24 7,32 12.25 2.95 .13 1.69 .15 100.18 797 CR
31.00S 113.12W 2453 < 10 R D E 50.47 15.09 10.28 7.06 11.90 2.99 .23 1.73 .15 99.90 868 CR
31.00S 113.12W 2453 < 10 R D E 50.57 15.09 10.35 7.32 12.15 2,92 ,20 1,82 ,16 100,58 867 CR
31.00S 113,12W 2453 < 10 R D E 50,26 14,52 10.90 7.00 11.92 3.12 .17 1.92 .16 99.97 865 CR
30.42S 078,98W 3820 M 38 S D E 50.73 16.58 8.96 7.59 11.98 2.70 .27 1.63 .17 100.61 F75 SH
25.525 177,90E 4320 5 29 M 205 E 49.73 15.79 9.76 6.86 11.80 2.36 .20 1.43 .16 98.09 647 DP
16.535 166,37E 4474 S 46 R 286 E 50,11 16,05 8,83 7,52 10,94 2,94 ,09 1.46 .11 98.05 733 DP
13.225 112.33W 2750 < 10 R D E 49.91 15.03 10.01 8.75 11.49 2.42 .10 1.51 .11 99.33 884 SC
13.225 112.33W 2750 < 10 R D E 49.61 15.24 10.14 8.62 11.47 2.42 .10 1.51 .11 99.22 882 SC
13.22S 112.33W 2750 < 10 R D E 50.96 15.04 10.23 7.90 11.78 2.32 .11 1.56 .12 100.02 883 SC
13.22S 112,33W 2750 < 10 R D E 50.20 14.06 11.59 6.12 10.94 3,11 ,15 2,10 ,18 96.45 875 SC
13.22S 112.33W 2750 < 10 R D E 50.66 14.20 11,71 6.17 11.00 3.08 .19 2.12 ,16 99,29 871 SC
13.22S 112.33W 2750 < 10 R D E 50.28 14.09 11.72 6,25 11,04 3,08 ,16 2.12 .18 98,92 878 SC
13,225 112.33W 2750 < 10 R D E 50.07 14,11 11,74 6.22 10.98 3.15 .20 2.09 .17 98.73 880 SC
13.22S 112.33W 2750 < 10 R D E 50.78 14.28 11.79 6.08 10.98 3.08 .18 2.13 .20 99.50 873 SC
13.22S 112.33W 2750 < 10 R D E 50.22 14.09 11.85 6.18 11,00 3,10 ,15 2.16 .16 98.91 877 SC
NUMBER 19 45
PACIFIC OCEAN
LAT. LONG. DEPTH AGE S T E SIO2 AL2O3 FEO* MGO CAO NA2O K2C TIO2 P2O5 SUM V<3-# SO
13.22S 112.33W 2750 < 10 R D E 49.78 14.08 11.86 6.19 10.95 3.13 .19 2.19 .20 98.57 881 SC
13.22S 112.33H 2750 < 10 R D E 49.7V14.23 11.87 6.18 10.93 3.16 .1? 2.18 .18 98.64 876 SC
13.22S 112.33W 2750 < 10 R 0 E 50.16 13.88 12.30 6.08 10.62 2.77 .19 2.24 .17 98.41 874 SC
13.22S 112.33W 275? < 10 R D E 50.02 13.63 12.57 6.01 10.70 2.80 .20 2.34 .19 98.46 879 SC
13.22S 112.33W 2750 < 10 R D E 50.91 13.25 12.59 6.10 10.92 2.72 .22 2.36 .19 99.26 870 SC
13.22S 112.33W 2750 < 10 R D E 50.74 13.40 12.93 5.76 10.78 2.72 .22 2.36 .18 99.09 872 SC
13.02S 101.52W 4296 M 21 R 319A E 51.57 14.91 9.88 7.72 12.75 2.41 .01 1.25 .05 100.55 707 DP
09.78S 102.69E 553b MS80 R 211 I 48.28 18.58 8.16 5.02 7.76 4.64 1.79 2.54 .71 97.48 648 DP
09.01S 083.53W 4482 - R 3206 E 51.21 15.31 9.98 7.63 11.86 2.72 .06 1.56 .11 100.44 708 DP
06.25S 107.23W 3082 < 10 R D E 50.82 15.60 9.34 7.81 12.78 2.40 .25 1.20 .10 100.30 794 CR
06.25S 107.23W 3082 < 10 R D E 50.78 15.37 9.39 7.76 12.78 2.38 .24 1.17 .08 99.95 793 CR
06.25S 107.23W 3082 < 10 R D E 50.73 15.19 9.55 7.96 12.29 2.46 .09 1.24 .09 99.60 791 CR
06.25S 107.23W 3082 < 10 R D E 49.58 15.29 9.60 7.82 12.57 2.53 .08 1.28 .09 98.84 788 CR
06.25S 107.23W 3082 < 10 R 0 E 50.63 15.22 9.60 8.00 12.50 2.54 .08 1.20 .07 99.84 792 CR
06.255 107.23W 3082 < 10 R D E 50,74 15.36 9.64 7.85 12.49 2.45 .10 1.14 .08 99.85 789 CR
06.25S 107.23W 3082 < 10 R D E 50.89 15.21 9.75 7.45 12.36 2.71 .07 1.31 .07 99.82 790 CR
00.96S 121.55W 4399 M 22 R 80 I 50.35 17.08 7.91 6.29 10.37 2.84 1.33 1.54 ,29 98,00 620 DP
01.45N 101,35W 3804 < 10 R C E 50.10 17.31 8.38 8.76 11.66 2.99 .07 1.19 .06 100.52 970 MY
01.45N 101,35W 3804 < 10 R C E 49.25 17.45 8.45 8.85 11.66 2.91 .07 1.17 .08 99.89 971 MY
01.45N 101.35W 3804 < 10 R C E 48.92 17.31 8.52 9.01 11.80 2.94 .05 1.18 .08 99.81 973 MY
01.45N 101.35W 3804 < 10 R C E 49.38 17.10 8.62 8.73 11.63 2.99 .07 1.17 .08 99.77 969 MY
01.45N 101.35W 3804 < 10 R C E 49.62 12.07 12.41 4.88 14.22 2.91 .39 2.74 ,17 99.41 972 MY
03.76N 175.08W 4962 S120 R 166 E 49.76 13.26 13.42 6.29 11.15 2.38 ,13 2.38 .21 98.98 637 DP
03.76N 175.08W 4962 S120 R 166 E 49.26 13.78 13.39 6.03 10.88 2.85 ,11 2.19 .18 98.67 638 DP
03.76N 175.08W 4962 5120 R 166 E 49.48 13.40 13.20 6.17 10.95 2.80 ,13 2.23 .17 98.53 639 DP
03.76N 175.08W 4962 S120 R 166 E 49.13 13.37 13.24 6.36 11.08 2.81 .13 2.21 .18 98.51 640 DP
03.76N 175.08W 4962 S120 R 166 E 49.49 13.37 13.24 6.39 10.94 2.80 .13 2.19 .18 98.73 641 DP
10.67N 173.55W 5407 SlOO R 169 E 50.75 14.35 11.25 7.62 12.41 1.95 .08 1.10 .08 99.59 642 DP
11.24N 150.29W 5230 S 72 R 163 E 48.99 15.78 9.85 8.38 12,64 2,28 ,05 1.22 .07 99.26 632 DP
11.24N 150.29W 5230 5 72 R 163 E 48.94 15.76 9.79 8.46 12,67 2,26 .06 1.18 .06 99.18 633 DP
11.24N 150.29W 5230 S 72 R 163 E 49.65 15.69 9.72 8.20 12.74 2.28 .05 1.19 .08 99.60 635 DP
11.24N 150,29W 5230 S 72 R 163 E 48,73 16.02 9.72 8.42 12,52 2,27 ,06 1.16 .06 98.96 634 DP
11.24N 150.29W 5230 5 72 R 163 E 48.95 15.83 9.77 8.44 12,54 2,28 ,06 1,25 .09 99.21 636 DP
15.61N 140.30W 4990 S 15 M 54 - 49.87 17.10 9.13 7.69 11.15 2.86 .11 1.05 .06 99.02 619 DP
19.13N 169.46W 22gO S 90 S 171 E 50,97 15.72 10,43 6.20 9.83 3.18 .59 2.17 ,22 99.31 644 DP
19.13N 169.46W 22gO S 90 S 171 E 50.97 15.56 10.54 5.97 9.69 3.16 .58 2.25 ,23 98.95 643 DP
46 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
PACIFIC OCEAN
LAT. LONG. DEPTH AGE S T E SI02 AL2O3 FEO* MGO CAO NA2O K20 TI02 P205 SUM VG-# SO
37.13N 127.56W 4758 M 38 R 32 I 51.11 12.60 15.62 4.85 9.38 2.23 .15 2.92 ,19 99.05 614 DP
37.13N 127.56W 4758 M 38 R 32 I 51.17 12.30 15.74 4.83 9.26 2.57 .16 2.93 .19 99.15 615 DP
37.13N 127.56W 4758 M 38 R 32 I 49.87 11.96 15.47 5.25 9.58 2.87 .15 2.86 .17 98.18 616 DP
37.13N 127.56W 4758 M 38 R 32 I 50.47 14.55 13.09 6.44 10.09 2.85 .50 2.18 .18 100.35 E29 DP
40.98N 130.11W 3273 S 13 R 36 E 49.85 16.57 9.72 8.52 12.40 1.84 .10 .87 .04 99.91 617 DP
40.98N 130.11W 3273 S 13 R 36 E 50.83 15.75 9.43 7.81 12.13 2.53 .11 1.35 .10 100.04 618 DP
52.57N 161.21W 4320 M 62 - 183 E 47.69 16.29 11.13 7.09 9.21 3.63 1,04 2.06 .39 98.53 645 DP
PACIFIC OCEAN GALAPAGOS SPREADING CENTER
LAT. LONG. DEPTH AGE S T E SI02 AL203 FEO* MGO CAO NA20 K20 TI02 P2O5 SUM VG-# SO
00.71N 085.50W 2523 < 1 R D E 50.27 12.71 15.35 5.56 9,94 2.45 .10 2.90 .24 99.52 A55 VG
00.71N 085.50W 2523 < 1 R D E 50.21 12.51 15.50 5.47 9.90 2.44 .13 2.68 .20 99.04 C52 VG
00.71N 085.50W 2523 < 1 R D E 50.87 12.47 15.53 5.19 10.08 2.37 .11 2.61 .23 99.46 C56 VG
00.71N 085.50W 2523 < 1 R D E 50.98 13.55 16.45 4.01 9.25 2.88 .16 3.58 .36 101.22 A54 VG
00.71N 085.50W 2523 < 1 R D E 50.85 11.84 16.52 3.57 8.87 2.83 .22 3.35 .34 98.39 A45 VG
00.71N 085.50W 2523 < 1 R D E 50,03 12,03 16,56 4,99 9,77 2,45 ,17 3,20 ,27 99,47 C48 VG
00.71N 085.50W 2523 < 1 R D E 50.43 11,94 U.62 3.46 8.87 2.81 .19 3.28 .33 97.93 A36 VG
00.71N 085.50W 2523 < 1 R D E 49.74 12.78 16.74 4.74 9.49 2.77 .13 3.18 .25 99.82 C46 VG
00.71N 085.50W 2523 < 1 R D E 50.92 11.75 16.75 3.54 8.63 2,80 ,23 3,33 ,40 98,35 A26 VG
00.71N 085,50W 2523 < 1 R D E 50,58 12,07 16,77 4,75 9,61 2.50 .17 3.15 ,27 99,87 598 VG
00.71N 085.50W 2523 < 1 R D E 49.62 12.33 16.78 4.82 9.48 2.49 .18 3.13 .28 99.11 C54 VG
00.71N 085.50W 2523 < 1 R D E 49.83 12.08 16,82 4,83 9.48 2,53 .15 3,21 ,26 99,19 A51 VG
00.71N 085,50W 2523 < 1 R D E 50,08 11,73 16,84 3.67 8.93 2.81 .21 3.31 .34 97,92 A31 VG
00.71N 085.50W 2523 < 1 R D E 50.31 12.37 16.85 4.94 9.70 2.51 .16 3.30 .28 100.42 C53 VG
00.71N 085.50W 2523 < 1 R D E 49.95 11.86 16.86 4.66 9.47 2.76 .18 3.20 .28 99.22 A44 VG
00.71N 085.50W 2523 < 1 R D E 50,53 11,89 16,87 4,90 9,58 2,60 ,16 3,05 ,24 99,82 596 VG
00.71N 085,50W 2523 < 1 R D E 50,12 12,18 16,87 4.93 9.48 2.52 ,15 3,18 ,27 99,70 600 VG
00.71N 085.50W 2523 < 1 R D E 49.82 12.23 16.87 4.88 9.55 2.66 .19 3.53 .32 100.05 A52 VG
00.71N 085.50W 2523 < 1 R D E 49.64 12.28 16.89 4.77 9.55 2.56 .13 3.15 .24 99,21 C55 VG
00.71N 085.50W 2523 < 1 R D E 49.80 11.60 16.90 4.59 9.61 2.50 .15 3.26 .27 98.68 A39 VG
00.71N 085.50w 2523 < 1 R D E 49.63 12.34 16.90 4.69 9.47 2.57 .16 3.18 .26 99.20 C51 VG
00.71N 085.50W 2523 < 1 R D E 49.62 11.86 16.91 4.78 9.60 2.37 ,17 3.16 ,28 98,75 C45 VG
00.71N 085.50W 2523 < 1 R D E 50.22 12.15 16.93 4.57 9.64 2.57 .13 3.31 .27 99.79 A58 VG
00.71N 085.50W 2523 < 1 R D E 50.26 11.93 16.93 4.68 9.69 2.58 .15 3.42 .33 99.97 A61 VG
00.71N 085,50W 2523 < 1 R D E 50,01 11,86 16,95 4,90 9,73 2.53 .15 3.10 .22 99.45 599 VG
NUMBER 19 47
PACIFIC OCEAN GALAPAGOS SPREADING CENTER
LAT. LONG. UEP1H AGE 5 T E 5102 AL203 FEO* MGO CAO NA20 K20 TI02 P205 SUM VG-# SO
00.71N 085.50W 2523 < 1 R D E 50.09 11.86 16.95 4.76 9.65 2.42 .17 3.33 .29 99.52 A24 VG
00.71N 085.50W 2523 < 1 R D E 50.11 11.63 16.96 4.54 9.54 2.44 .15 3.29 .27 98.93 A 1 VG
00.71N 085.50W 2523 < 1 R D E 49.30 12.02 16.96 4.98 9.56 2.34 .17 3.23 ,26 98.82 A25 VG
00.71N 085.50W 2523 < 1 R D E 49.84 11.95 16.96 4.80 9.70 2.39 .15 3.22 .25 99.26 A34 VG
00.71N 085.50W 2523 < 1 R D E 50.45 12.37 16.98 5.14 9.95 2.56 .14 3.51 .28 101.38 A59 VG
00.71N 085.50W 2523 < 1 R D E 50.05 12.28 16.99 4.73 9.81 2.55 .16 3.19 .28 100.04 967 VG
00.71N 085.50W 2523 < 1 R D E 50.18 11.76 16.99 4.75 9.47 2.46 .17 3.27 .26 99.31 A48 VG
00.7iN 085.50k 2523 < 1 R D E 49.32 11.74 17.01 4.92 9.65 2.48 .16 3.27 .25 98.80 Al5 VG
00.71N 085.50W 2523 < 1 R D E 49.86 11.74 17.01 4.85 9.65 2.47 .17 3.36 .27 99.38 A29 VG
00.71N 085.50W 2523 < 1 R D E 50,55 11.48 17.02 4.80 9.57 2.30 .18 3.11 ,27 99,28 597 VG
00.71N 085,50W 2523 < 1 R D E 50.68 11.89 17.02 4.67 9.63 2.67 .13 3.32 .27 100.28 A38 VG
00.71N 085.50W 2523 < 1 R D E 50.62 11.66 17.04 4.86 9.63 2,51 .16 3.18 .30 99.96 A 4 VG
00.71N 085.50W 2523 < 1 R D E 49.68 11.72 17.04 4.69 9.58 2.48 .16 3.33 .26 98,94 A32 VG
00.71N 085.50W 2523 < 1 R D E 50.06 11.92 17.05 4.71 9.56 2.44 .14 3.24 ,25 99,37 A41 VG
00.71N 085.50W 2523 < 1 R D E 49.74 11,71 17.06 4.78 9.61 2.50 .17 3.27 .25 99.09 A14 VG
00.71N 085.50W 2523 < 1 R D E 49.90 11.80 17.07 4.92 9.58 2.47 .14 3.23 .30 99.41 A35 VG
00.71N 085.50w 2523 < 1 R D E 50.22 11.86 17.08 5.00 9.72 2.42 .17 3.31 .25 100,03 A17 VG
00.71N 085.50W 2523 < 1 R D E 50.06 11.98 17.10 4.78 9.70 2.45 .16 3.32 .28 99.83 A18 VG
00.71N 085.50W 2523 < 1 R D E 49.49 11,91 17.10 4.71 9.53 2.47 .18 3.35 .27 99.01 A30 VG
00.71N 085.50W 2523 < 1 R D E 50,53 11.88 17.11 4.72 9.84 2.42 .14 3.29 ,27 100,20 A37 VG
00.71N 085,50W 2523 < 1 R D E 50,57 12.18 17.11 4.84 9.68 2,51 ,16 3,38 ,34 100,77 A57 VG
00.71N 085.50W 2523 < 1 R D E 50.10 11.83 17.12 4.92 9.80 2.49 .16 3.27 .28 99,97 A 7 VG
00.71N 085.50W 2523 < 1 R D E 50.38 12.21 17.14 4.88 9.76 2.52 .13 3.21 .29 100.52 AOO VG
00.71N 085.50W 2523 < 1 R D E 50,46 11.51 17.16 4.64 9.70 2.34 .17 3.31 .30 99,59 A 5 VG
00.71N 085.50W 2523 < 1 R D E 49.79 11.72 17.16 4.76 9.69 2.49 ,17 3.19 ,28 99.25 A 8 VG
00.71N 085.50W 2523 < 1 R D E 49.75 12,01 17,16 4,81 9.73 2,44 ,15 3.28 .27 99.60 A16 VG
00.71N 085.50W 2523 < 1 R D E 50.04 11.62 17.17 5.01 9.73 2.45 .14 3.24 .27 99.67 A10 VG
00.71N 085.50W 2523 < 1 R D E 49.34 12.18 17.17 4.32 9.44 2.58 .14 3.42 .27 98.86 A40 VG
00.71N 085,50W 2523 < 1 R D E 49.42 11.85 17.18 4.49 9,30 2,58 .18 3.36 ,29 98,65 A20 VG
00.71N 085,50W 2523 < 1 R D E 50.37 12.20 17.21 3.57 8.75 2.75 .22 3.65 .35 99.07 A23 VG
00.71N 085.50W 2523 < 1 R 0 E 49.98 12.25 17.21 3.85 9.18 2.72 .18 3.45 .32 99.14 C58 VG
00.71N 085.50W 2523 < 1 R D E 49.56 11.77 17.21 5.01 9.73 2.45 .16 3.21 .26 99,36 C60 VG
00.71N 085,50W 2523 < 1 R D E 50,05 11.81 17.24 5.03 9.72 2.49 .18 3.31 .30 100.13 A02 VG
00.71N 085.50W 2523 < 1 R D E 49.95 11.92 17.28 4.81 9.31 2.53 .18 3.20 .25 99,43 C57 VG
00.71N 085,50W 2523 < 1 R D E 50,18 11,91 17.32 4.06 9.03 2.77 .18 3.36 .30 99,11 C47 VG
00.71N 085.50W 2523 < 1 R 0 E 49.83 11.73 17,36 3.99 8.94 2,73 .20 3,56 ,33 98.67 A22 VG
48 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
PACIFIC OCEAN GALAPAGOS SPREADING CENTER
LAT. LONG. DEPTH AGE S T E SI02 AL2O3 FEO* MGO CAO NA2O K20 TI02 P2O5 SUM VG-# SO
0O.71N 085.5OW 2523 < 1 R D E 49.95 11.63 17.36 4.31 9.54 2.46 .17 3,39 .27 99.08 A27 VG
00.71N 085.50W 2523 < 1 R D E 49.99 11.92 17.40 4.25 9.06 2.75 .17 3.48 .30 99.32 C49 VG
00.71N 085.50W 2523 < 1 R D E 48.63 11.75 17.50 4.96 9.51 2.48 .18 3.65 .33 98.99 A56 VG
00.71N 085.5OW 2523 < 1 R D E 49.72 11.76 17.53 4,34 9.22 2.67 .19 3.53 .32 99.28 C50 VG
00.71N 085.50w 2523 < 1 R D E 50.48 11.44 17.56 3.94 9.32 2.56 .18 3.52 .33 99.33 A46 VG
00.71N 085.50W 2523 < 1 R D E 50.36 11.58 17.63 4.09 9.22 2.61 ,18 3,56 .31 99.54 A49 VG
00.71N 085.50W 2523 < 1 R D E 50.04 11.60 17.89 3.95 9.27 2.60 .19 3.69 .35 99.58 A 6 VG
00.71N 085.50W 2523 < 1 R D E 49.65 11.62 17.90 3.81 8.86 2.59 .21 3.59 .33 98.56 A42 VG
00.71N 085.50w 2523 < 1 R D E 49.68 11.42 18.09 4.33 9,14 2,60 ,15 3,94 ,33 99.68 A60 VG
00.71N 085.50W 2523 < 1 R D E 4g,46 11.30 18.19 4.31 9.08 2.64 .20 3.69 .31 99.18 A21 VG
00.71N 085.50W 2523 < 1 R D E 48.75 11.54 18.36 4.30 9.07 2.56 .21 3.69 .34 98.82 A 3 VG
00.71N 085.50W 2523 < 1 R D E 50.29 11.50 18.36 4.36 9.28 2.46 ,17 3.64 ,29 100,35 C59 VG
00.71N 085.50W 2523 < 1 R D E 49.43 11.26 18.43 4.34 9.19 2.50 .18 3.66 .30 99.29 A28 VG
00.71N 085.50W 2523 < 1 R D E 49.16 11.13 18.46 4.24 9.21 2.48 .18 3.76 .30 98.92 A47 VG
00.71N 085.50w 2523 < 1 R D E 49.17 11.14 18.50 4.24 9.10 2.52 .19 3.69 .32 98,87 All VG
00.71N 085,50W 2523 < 1 R D E 49.87 11,12 18.54 4.29 9.29 2.50 .19 3.73 ,30 99,83 A 9 VG
00.71N 085.50W 2523 < 1 R D E 49.15 11.27 18.66 4.21 9.33 2.48 .19 3.76 .31 99.36 A12 VG
00.82N 086.13W 2500 < 1 R D E 51.35 13.21 13.43 6.12 10.74 2.30 .10 2.14 .18 99.57 C62 CL
00.82N 086.13W 2500 < 1 R D E 51.58 13.14 13.84 5.20 10.10 2.64 .12 2.14 .21 98.97 C6l CL
00.82N 086.13W 2500 < 1 R D E 51.14 12.90 14.10 5.50 10.11 2.60 .13 2.17 .23 98.88 C63 CL
01.04N 085.12W 27g8 < 1 R D E 50.29 16.21 8.52 7.94 11.71 2.79 .08 1.55 .19 99.28 D49 VG
01.04N 085.12W 2798 < 1 R D E 50.74 16.39 8.56 8.04 11.88 2.74 .06 1.45 .13 99.99 594 VG
01.04N 085.12W 2798 < 1 R D E 49.34 16.30 8.56 8.07 11.90 2.75 .07 1.52 .12 98.63 D48 VG
01.04N 085.12W 2798 < 1 R D E 49.97 16.41 8.58 7.86 11.94 2.77 .07 1.51 .15 99.26 592 VG
01.04N 085.12W 27g8 < 1 R D E 50.31 16.21 8.60 8.38 11.97 2.82 .07 1.44 .13 99.93 595 VG
01.04N 085.12W 2798 < 1 R D E 50.23 16.27 8.60 7.92 11.98 2.81 .10 1.45 .16 99.52 D50 VG
01.04N 085,12W 2798 < 1 R D E 50.25 16,54 8.70 8.02 11.89 2.71 .07 1.41 .13 99.72 593 VG
01.04N 085.12W 2798 < 1 R D E 49,89 16.26 8.72 8.19 11.98 2.74 ,07 1.45 .12 99.42 591 VG
02.20N 101.42W - < 1 R D E 51.05 14.91 9.64 6.83 11.50 3.03 .13 1.49 .11 98.69 C66 CL
02.42N 095.41W 2268 < 1 R D E 50.66 15.54 9.20 7.97 12,31 2,23 ,07 1,22 .07 99.27 D38 VG
02.42N 095.41W 2268 < 1 R D E 51.38 15.49 9.22 7.81 12.19 2.19 .08 1.13 .06 99.55 605 VG
02.42N 095.41W 22&8 < 1 R D E 50.35 15.62 9.23 8.4O 12.42 2.20 .14 1.20 .08 99.64 D41 VG
02.42N 095.41w 2268 < 1 R D E 50.21 15.47 9.28 8.04 12.41 2.21 .11 1.17 .05 98.95 D40 VG
02.42N 095.41W 2268 < 1 R D E 50.70 15.44 9.29 8.11 12.20 2.23 ,12 1.15 .06 99.30 D60 VG
02.42N 095.41i* 2268 < 1 R D E 50.36 15.62 9.34 8.24 12.30 2.25 .09 1.18 .08 99.46 D59 VG
02.42N 095.41W 2268 < 1 R D E 50.37 15.52 9.39 7.66 12.28 2.27 .13 1.11 .11 98.84 D43 VG
NUMBER 19 49
PACIFIC OCEAN GALAPAGOS SPREADING CENTER
LAT. LONG. DEPTH AGE S T E SIO2 AL2O3 FEO* MGO CAO NA20 K2C TIO2 P2O5 SUM VG-# SO
02.42N 095.41W 2268 < I R D E 50.74 15.52 9.40 8.25 12.20 2.22 .11 1.21 .08 99.73 D39 VG
02.42N 095.41W 2268 < 1 R D E 51.89 15.47 9.40 8.17 12.31 2.26 .12 1.17 ,08 100.87 D58 VG
02.42N 095.41W 2268 < 1 R D E 51.50 15.58 9.42 7.83 12.10 2.23 ,09 1.15 .09 99.99 D57 VG
02.42N 095.41W 2268 < 1 R D E 50.80 15.55 9.50 8.19 12.16 2.28 .12 1.22 .06 99.88 D42 VG
02.42N 095.41W 2268 < 1 R D E 51.83 15.34 9.bO 8.42 12.31 2.22 .11 1.24 .08 101.05 D46 VG
02.42N 095.41W 2268 < 1 R D E 50.54 15.70 9.53 8,34 12,32 2,18 ,11 1.18 .08 99.98 D44 VG
02.42N 095.41W 2268 < 1 R D E 50.93 15.52 9.59 8.14 12.13 2.23 .11 1.21 .05 99.91 D45 VG
02.42N 095.41W 2268 < 1 R D E 50,50 15,28 9.62 7.60 12.41 2.30 .11 1.23 .11 99.16 047 VG
02.44N 095.62W 2469 < 1 R D E 49.69 16.34 8.65 8.40 12.42 2.23 .07 .98 .10 98.88 C70 VG
02.44N 095.62W 2469 < 1 R D E 50.42 16.44 8.69 8.41 12.11 2.21 .08 .97 .08 99.41 0 9 VG
02.44N 095.62W 2469 < 1 R D E 50.04 16.23 8.70 8.16 12.73 2.05 .06 1.00 .08 99.05 C93 VG
02.44N 095.62W 2469 < 1 R D E 50.49 15.96 8.71 8.62 12.17 2.25 .07 1.01 .08 99.36 C90 VG
02.44N 095.62W 2469 < 1 R D E 50.12 16.52 8.71 8.62 12.41 2.19 .06 1.06 .09 99.78 C98 VG
02.44N 095,62W 2469 < 1 R D E 50.02 15.91 8.75 8.45 12.25 2.25 .08 1,01 ,05 98,77 D22 VG
02.44N 095.62W 2469 < 1 K D E 50.08 16.87 8.76 8.27 12.41 2.22 .07 1.04 .07 99.79 D10 VG
02.44N 095.62W 2469 < 1 R D E 49.58 15.98 8.76 8.69 12,32 2,20 .08 1.06 .08 98.75 D16 VG
02.44N 095.62W 2469 < 1 R D E 50.19 16.36 8.77 8.54 12.36 2.21 .08 1.01 .07 99.59 D18 VG
02.44N 095.62W 2469 < 1 R D E 50.70 16.62 8.78 8.63 12.57 2.23 .09 1.02 .08 100.72 C82 VG
02.44N 095,62W 2469 < 1 R D E 50,62 16,49 8,79 8,53 12.34 2.24 .04 1.04 ,06 100,15 D 8 VG
02.44N 095.62W 2469 < 1 R D E 49.45 16.05 8.80 8.55 12,49 2.18 .06 1.12 .03 98.73 D24 VG
02.44N 095.62W 2469 < 1 R D E 49.96 16.37 8.80 8.38 12,13 2,25 .11 1.15 .08 99.23 D32 VG
02.44N 095.62W 2469 < 1 R D E 50.39 15.79 8.81 8.39 12.86 2.04 .07 1.03 .05 99.43 D20 VG
02.44N 095.62W 2469 < 1 R D E 50.25 16.00 8.83 8,36 12,23 2,21 .07 1.17 .10 99.22 D36 VG
02.44N 095.62W 2469 < 1 R D E 50,27 15.90 8.85 8.45 12.51 2.22 .07 1.07 .09 99.43 C67 VG
02.44N 095.62W 2469 < 1 R D E 50.22 16.30 8.85 8.67 12.38 2.21 .07 .99 .08 99.77 C72 VG
02.44N O95.62W 2469 < 1 R D E 49.57 16.24 8.86 8.50 12.31 2.18 .10 1.08 .08 98.92 D15 VG
02.44N 095.62W 2469 < 1 R D E 49.92 16.15 8.86 8.57 12.37 2.19 .08 1.04 .06 99.24 D17 VG
02.44N 095.62W 2469 < 1 R D E 49.93 16.31 8.86 8.54 12.39 2.23 .09 1.12 .06 99.53 D34 VG
02.44N 095.62W 2469 < 1 R D E 49.90 16.74 8.88 8.19 12.63 2.22 .06 .92 ,06 99.60 D52 VG
02.44N 095.62W 2469 < 1 R D E 50.31 16.57 8.89 8.48 12.37 2.1.9 .05 1.03 .08 99.97 D02 VG
02.44N 095.62W 2469 < 1 R D E 49.64 16.51 8.91 8.79 12.44 2.23 .07 I.00 .07 99.66 C78 VG
02.44N 095.62W 2469 < 1 R D E 49.87 16.27 8.93 8.63 12.35 2.20 .07 1.09 .08 99.49 D53 VG
02.44N 095.62W 2469 < 1 R D E 50.09 16.07 8.94 8.53 12.45 2.22 .09 1.07 .09 99.55 D19 VG
02.44N 095.62W 2469 < 1 R D E 50.26 16.60 8.94 8.39 12.42 2.26 .07 1,05 ,09 100,08 D54 VG
02.44N 095.62W 2469 < 1 R D E 51.15 16.08 8.95 8.96 12.44 2.19 .07 1.12 .06 101.02 C71 VG
02.44N 095.62W 2469 < 1 R D E 50.78 16.10 8.95 8.46 12.43 2.19 .05 1.13 .05 100.14 D28 VG
50 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
PACIFIC OCEAN GALAPAGOS SPREADING CENTER
LAT. LONG, DEPTH AGE S T E SI02 AL2O3 FEO* MGO CAO NA2O K20 TI02 P205 SUM VG-# SO
02.44N 095.62W 2469 < 1 R D E 50.69 15.96 8.97 8.74 12.55 2.25 .07 1.13 .06 100.42 601 VG
02.44N 095.62W 2469 < 1 R D E 49.82 16.04 8.97 8.32 11.99 2.24 .06 1.03 .06 98.53 602 VG
02.44N 095.62W 2469 < 1 R D E 50.77 16.42 8.97 8.63 12.37 2.17 .08 1.04 .06 100.51 D23 VG
02.44N 095.62W 2469 < 1 R D E 49.75 15.89 8.97 8.58 12.64 2.21 .08 1.08 .08 99.28 D27 VG
02.44N 095.62W 2469 < 1 R D E 49.75 16.10 8.99 8.34 12.28 2.23 .08 1.08 .05 98.90 D2l VG
02.44N 095.62W 2469 < 1 R D E 49.84 16.23 9.00 8.50 12.80 2.12 .05 1.04 .07 99.65 D30 VG
02.44N 095.62W 2469 < 1 R D E 50.29 16.42 9.00 8.56 12.76 2.19 .05 1.01 .06 100.34 D37 VG
02.44N 095.62W 2469 < 1 R D E 50.73 15.73 9.01 8.21 12.45 2.20 ,07 1.09 .09 99.58 C68 VG
02.44N 095.62W 2469 < 1 R D E 50.97 16.11 9.01 8.31 12.45 2.24 ,07 1.10 .09 100.35 C85 VG
02.44N 095.62W 2469 < 1 R D E 50.26 16.42 9.02 8.28 12.12 2.25 .07 1.09 .09 99.60 D 3 VG
02.44N 095.62W 2469 < 1 R D E 50.05 16.54 9.02 8.31 12.55 2.18 .07 .95 .08 99.75 D 6 VG
02.44N O95,62W 2469 < 1 R D E 50,22 15,87 9.02 8.35 12,56 2,23 ,08 1,16 ,05 99,54 D14 VG
02.44N 095.62W 2469 < 1 R D E 50.14 16.36 9.03 8.12 12.20 2.26 .10 1.03 .08 99.32 C88 VG
02.44N 095.62W 2469 < 1 R D E 49.80 15.69 9.04 8.37 12.73 2.19 .05 .93 .03 98.83 D25 VG
02.44N 095,62W 2469 < 1 R D E 50,86 16.31 9.06 8,29 12,30 2.18 .07 1.11 .10 100,28 C92 VG
02.44N 095.62W 2469 < 1 R D E 49.40 16.03 9.07 8.36 12.49 2.18 .05 1.03 .05 98.66 D12 VG
02.44N 095.62w 2469 < 1 R D E 50.22 16.06 9.07 8.98 12.48 2.15 ,06 1.03 .04 100,09 Dl3 VG
02.44N 095.62W 2469 < 1 R D E 50,30 16,43 9.08 8.28 12.36 2.23 .05 1.08 .08 99,89 C95 VG
02,44N 095.62W 2469 < 1 R D E 50.73 16.24 9.08 8.14 12.31 2.21 .08 1.08 .08 99.95 D 1 VG
02.44N 095.62W 2469 < 1 R D E 50.07 16.35 9.08 8.27 12.80 2.13 .05 .91 .09 99.75 D 7 VG
02.44N 095,62W 2469 < 1 R D E 50,24 16,33 9,09 8,38 12,32 2.23 .07 1.07 .08 99.81 C77 VG
02.44N 095.62w 2469 < 1 R D E 49.75 16.68 9.09 8.16 12.74 2.21 .05 .94 .05 99.67 C89 VG
02.44N O95.62W 2469 < 1 R D E 50,23 16,16 9.09 8.23 12.63 2.16 .05 ,97 ,04 99.56 D31 VG
02.44N 095.62W 2469 < 1 R D E 50,42 15,95 9.10 8.38 12.50 2.14 ,03 1.06 .07 99.65 D26 VG
02.44N 095.62W 2469 < 1 R D E 50.87 16.43 9.11 8.70 12.53 2.19 .07 1.10 .06 101.06 D33 VG
02.44N 095,62W 2469 < 1 R D E 49.08 16.27 9.12 8.61 12.74 2.19 .08 .97 .06 99.12 D35 VG
02.44N 095,62W 2469 < 1 R D E 49.48 16.54 9.13 8.68 12.58 2.18 ,06 ,98 ,10 99.73 C75 VG
02.44N 095.62h 2469 < 1 R D E 49.78 16.42 9.13 8.65 12.69 2.19 .07 .95 .08 99.96 C8l VG
02.44N 095.62W 2469 < 1 R D E 50.66 16.23 9.13 8.48 12.71 2.21 .04 .97 .08 100.51 C97 VG
02.44N 095.62W 2469 < 1 R D E 50.31 16.46 9.14 8.44 12.54 2.16 .07 .91 .07 100.10 D 5 VG
02.44N 095.62W 2469 < 1 R D E 50.20 16.77 9.16 8.30 12.77 2.19 .05 .97 .08 100.49 C99 VG
02.44N 095.62W 2469 < 1 R D E 50.07 16.43 9.18 8.30 12.60 2.21 .04 1.00 .08 99.91 C86 VG
02.44N 095.62W 2469 < 1 R D E 50,65 15.77 9.19 8.23 12.18 2.27 ,07 1.11 .09 99.56 C73 VG
02.44N 095.62W 2469 < 1 R D E 50.17 16.30 9.19 8.34 12.60 2.18 .04 .97 .09 99.88 C91 VG
02.44N 095.62W 2469 < 1 R D E 49.57 15.44 9.21 8.49 12.46 2.28 .07 1.09 .12 98.73 Dll VG
NUMBER 19 51
PACIFIC OCEAN GALAPAGOS SpREADING CENTER
LAT. LONG. DEPTH AGE S T E SIO2 AL2O3 FEO* MGO CAO NA2O K2O TIO2 P2O5 SUM VG-# SO
02.44N 095.62W 2469 < 1 R D E 50.39 16.44 9.22 8.08 12.70 2.18 ,05 .95 .08 100.09 C87 VG
02.44N 095.62W 2469 < 1 R D E 49.99 16.18 9.24 8.29 12.68 2.18 .04 .98 .09 99.67 D 4 VG
02.44N 095.62W 2469 < 1 R D E 50.25 16.11 9.25 8.49 12.50 2.21 .04 1.00 .08 99.93 DOO VG
02.44N 095.62W 2469 < 1 R D E 50.50 16.48 9.26 8.50 12.72 2.12 .05 .97 .08 100.68 C94 VG
02.44N 095.62W 2469 < 1 R D E 49.65 15.95 9.27 8.26 12.85 2.17 .07 1.01 .06 99.29 C79 VG
02.44N 095.62W 2469 < 1 R D E 50.51 16.26 9.27 8.72 12.80 2.19 .06 .99 ,05 100.85 D29 VG
02.44N 095.62W 2469 < 1 R D E 50.43 16.33 9.29 8.23 12.56 2.12 .06 .95 ,08 100,05 C80 VG
02.44N 095,62W 2469 < 1 R D E 49.79 16.42 9.32 8.42 12.43 2.17 .04 .90 .07 99.56 C74 VG
02.44N 095.62W 2469 < 1 R D E 49.82 16.03 9.32 8.23 12.65 2.19 .05 1.00 .09 99.38 C83 VG
02.44N 095,62W 2469 < 1 R D E 49.68 16,40 9.32 8.27 12.67 2.18 .04 .99 .08 99.63 C96 VG
02.44N 095.62W 2469 < 1 R D E 50.08 16,34 9.33 8.42 12.46 2.17 .04 .99 .09 99.92 C76 VG
02.44N 095.62W 2469 < 1 R D E 50.78 15.83 9.45 8.32 12.44 2.16 .05 1.07 ,06 100.16 D51 VG
02.44N 095.62W 2469 < 1 R D E 49,29 16,27 9.50 8.11 12.76 2.17 .05 .94 .08 99.17 C84 VG
02.60N 095.33W 1308 < 1 R D E 50.78 14.31 11.52 7.45 11.00 2.30 .12 1.55 .13 99.16 606 VG
02.60N 095,33W 1308 < 1 R D E 49.93 14.65 11,57 7.59 10.87 2.31 .15 1.58 .12 98.77 D63 VG
02.60N 095.33W 1308 < 1 R D E 50.95 14.09 11.83 7.21 11.07 2.31 .16 1.64 .13 99.39 D62 VG
02.70N 095,24W 25<y7 < 1 R 0 E 71.04 11.88 4.28 .17 2.41 4.31 1.63 .62 .08 96.42 C27 VG
02.70N 095.24W 2597 < 1 R D E 70.99 12.26 4.31 .21 2,56 4,44 1.68 .65 .05 97.15 Cll VG
02.70N 095.24W 2597 < 1 R D E 68.59 12.36 4.53 .30 2.80 3.72 1.72 .56 .04 94.62 C25 VG
02.70N 095.24W 2597 < 1 R D E 69.42 12,57 4,56 ,25 2,61 4,24 1,59 .70 ,06 96,00 C16 VG
02.70N 095.24W 2597 < 1 R D E 70.58 12.29 4.59 .23 2.60 4.50 1.57 .65 .07 97.08 C29 VG
02.70N 095.24W 259? < 1 R D E 69.00 12.61 4.68 .22 2.65 4.53 1,49 .64 ,06 95,88 C28 VG
02.70N 095,24W 2597 < 1 R D E 70.76 12.69 4,73 ,27 2.79 4.35 1.59 .60 .05 97.83 C21 VG
02.70N 095.24W 2597 < 1 R D E 68.43 11.93 4.81 .23 2.67 4.31 1.55 .71 .08 94.72 C 6 VG
02.70N 095.24W 259? < 1 R D E 70,22 13,00 4.85 .30 3.00 4,36 1,51 .56 ,07 97,87 C17 VG
02.70N 095.24W 2597 < 1 R D E 70.20 12.28 4,88 ,28 2,61 4.33 1,59 .57 .05 96,79 C18 VG
02.70N 095.24W 2597 < 1 R D E 69.69 12.38 4.94 .30 2.63 4.40 1.37 .63 .06 96.40 C30 VG
02.70N 095,24W 2597 < 1 R D E 69,74 12,00 4.96 .41 2.60 4.15 1.60 ,57 ,06 96,09 C 5 VG
02.70N 095,24W 259? < 1 R D E 69,42 12,65 4,96 ,57 3,02 4.35 1.53 .58 .04 97.12 C23 VG
02.70N 095,24w 259? < 1 R D E 69,74 12.10 5.03 ,35 2,46 4.43 1.47 .56 ,08 96.22 C 8 VG
02.70N 095,24W 2597 < 1 R D E 68.72 12.57 5,04 ,43 3,16 4.33 1,47 ,64 .07 96.43 C 9 VG
02.70N 095.24W 2597 < 1 R D E 69.65 12.57 5.06 .54 3.03 4.41 1.29 .56 ,06 97.17 C13 VG
02.70N 095,24W 2597 < 1 R D E 69.52 12.23 5.09 .33 2.80 4.17 1,54 ,72 .08 96.48 C15 VG
02.70N 095.24W 2597 < 1 R D E 68.50 12.65 5.12 .44 3.08 4.29 1.47 .59 .07 96.21 CIO VG
02.70N 095.24W 2597 < 1 R D E 68.94 12.51 5.16 .37 2.61 4,34 1,66 .63 .10 96.32 C24 VG
52 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
PACIFIC OCEAN GALAPAQOS SpREADING CENTER
LAT, LONG, DEPTH AGE S T E SI02 AL2O3 FEO# MGO CAO NA2O K20 TI02 P205 SUM VG-* SO
02.70N 095.24W 2597 < 1 R D E 71,06 12.60 5.27 .50 2.95 4.21 1.50 .58 .06 98.73 C12 VG
02.70N 0g5.24W 2597 < 1 R D E 70.71 12.56 5.28 .46 3.03 4.06 1,32 .60 ,06 98,08 997 VG
02.70N 095,24W 2597 < 1 R D E 70,77 12,30 5,30 ,43 2,92 4.14 1,30 ,61 ,05 97,82 996 VG
02.70N 095.24W 2597 < 1 R D E 69.74 12.47 5.38 .52 3.04 4.19 1.53 .59 .06 97.52 C19 VG
02.70N 095.24W 2597 < 1 R D E 69,58 12,13 5.41 .42 2.82 4,38 1,24 ,63 ,07 96,68 C 7 VG
02.70N 095.24W 2597 < 1 R D E 68.76 12.01 5,70 .45 3.05 4.26 1.62 .72 .09 96.66 C22 VG
02.70N 095.24W 2597 < 1 R D E 69.64 12.45 5.88 .47 3.16 4,28 1,21 .50 ,09 97,68 982 VG
02.70N 095,24W 2597 < 1 R D E 69,81 12.60 5.90 .37 3.06 4.35 1.15 .48 .08 97.80 603 VG
02.70N 095.24W 2597 < 1 R D E 69.36 12,00 5.96 .48 2.84 4.29 1.39 .52 .09 96.93 C14 VG
02.70N 095.24W 2597 < 1 R D E 68,82 11.93 5.98 .50 2.98 4,21 1,38 ,50 ,07 96,37 C 4 VG
02.70N 095.24W 2597 < 1 R D E 68.71 11.95 5.99 .40 2.95 4.29 1.45 .54 .06 96.34 C20 VG
02.70N 095.24W 2597 < 1 R D E 70.39 12,24 6,00 ,46 2,99 4,25 1.21 .51 .07 98.12 604 VG
02.70N 095.24W 2597 < 1 R D E 69.77 12.05 6.11 .44 2.94 4.28 1.41 .52 .08 97.60 C02 VG
02.70N 095.24W 2597 < 1 R D E 68.98 12.02 6.12 .46 2.99 4.32 1.34 .58 .07 96.88 C26 VG
02.70N 095.24W 2597 < 1 R D E 57.11 13.42 12.02 2.75 6.79 3.26 ,57 1.74 .18 97.84 C44 VG
02.70N 095,24W 2597 < 1 R D E 57.06 13.54 12.22 2.74 6.95 3.36 .59 1.78 .17 98.41 C34 VG
02.70N 095.24W 2597 < 1 R D E 50.89 13.52 13.55 5.45 10.31 2.64 .16 1.95 .16 98.63 D68 VG
02.70N 095.24W 2597 < 1 R D E 51.53 13.51 13.75 5.77 10,46 2,55 .20 1.99 .12 99.88 D65 VG
02.70N 095.24W 2597 < 1 R D E 51.61 13.20 13.76 5.87 10.43 2.55 .14 1.91 .16 99.63 999 VG
02.70N 095.24W 2597 < 1 R D E 51.41 13.13 13.80 5.73 10.33 2.54 .15 1.85 .16 99.10 C39 VG
02.70N 095,24W 2597 < 1 R D E 51,22 13,26 14,05 5,42 10,03 2,56 ,16 2.07 .16 98.93 995 VG
02.70N 095,24W 2597 < 1 R D E 51,52 13.09 14.07 5.59 10,20 2,48 ,16 2,07 ,17 99,35 994 VG
02.70N 095.24W 2597 < 1 R D E 51.35 13.25 14.11 5.74 10.18 2.57 .17 2.08 .16 99.61 C37 VG
02.70N 095.24W 2597 < 1 R D E 51.13 13.39 14.14 5.62 10.19 2.60 .17 2.04 .17 99.45 C38 VG
02.70N 095.24W 2597 < 1 R D E 51.61 13.10 14.15 5.55 10.00 2.60 .18 2.03 .14 99.36 C43 VG
02.70N 095.24W 2597 < 1 R D E 52.62 12.97 14.18 5.44 10.20 2.40 ,21 2.07 .18 100.27 C35 VG
02.70N 095.24W 2597 < 1 R D E 51.87 12.97 14.24 5.65 10.04 2.59 .17 2.07 .15 99.75 C42 VG
02.70N O95.24W 2597 < 1 R D E 52.16 12.78 14.29 5.64 10.09 2.56 .18 2.08 .16 99.94 D56 VG
02.70N 095.24W 2597 < 1 R D E 51.79 13.27 14.35 5.95 10.16 2.44 .19 2.08 .15 100.38 C33 VG
02.70N 095.24W 2597 < 1 R D E 51.43 12.57 15.43 4.38 9.06 2.82 .28 2.48 .24 98.69 D70 VG
02.70N 095,24W 2597 < 1 R D E 51,87 12,63 15,52 4,28 8.97 2.82 .29 2.39 .22 98,99 D66 VG
02.70N 095.24W 2597 < 1 R D E 51.74 12.36 15.71 4.61 9.10 2.60 .29 2.45 .22 99.08 C41 VG
02.70N O95.24W 2597 < I R D E 52.35 12.52 15.72 4.37 9.16 2.76 .28 2.49 .25 99.90 998 VG
02.70N 095.24W 2597 < 1 R D E 51.64 12.50 15.72 4.88 9.03 2.70 .31 2.54 .20 99.52 C36 VG
02.7QN 095.24W 2597 < 1 R D E 51.87 12.77 15.80 4.40 9.08 2.71 .26 2.46 .22 99.57 C40 VG
NUMBER 19 53
PACIFIC OCEAN GALAPAGOS SpREADING CENTER
LAT. LONG. DEPTH AGE 5 T E SIO2 AL2O3 FEO* MGO CAO NA2O K20 TIO2 P205 SUM VG-# SO
02.70N 095.24W 2b9~l < 1 R D E 52.42. 12.72 15.80 4.47 9.01 2.76 ,32 2.54 .24 100.28 D55 VG
02.70N 095.24W 25y7 < 1 R Q E 51.94 12.43 15.97 4.87 8.95 2.60 .33 2.49 .20 99.78 C32 VG
03.20N 083.04W 2600 < 1 R D E 50.89 15.19 8.99 7.75 12.52 2.55 .05 1.16 .07 99.17 C65 CL
03.20N 083.04W 2600 < 1 R 0 E 50.47 15.29 9.06 8.21 12.54 2.18 .02 1.07 .06 98.90 C64 CL
03.20N 083.34W 2468 < 10 R D E 50.73 13.01 14.12 5.67 10.30 2.51 .11 2.28 .18 98.91 891 SC
03.20N 083.34W 2468 < 10 R D E 50.36 13.01 14.22 5.72 10.34 2.53 ,13 2.26 ,19 98.76 887 SC
03.20N 083.34W 2468 < 10 R D E 51.58 13.24 14,23 4.87 9.86 2.78 ,16 2,26 ,22 99,20 886 SC
03.20N 083.34W 2468 < 10 R D E 51.31 13.02 14,29 5.21 10.U 2.54 .16 2.32 .20 99.21 885 SC
03.20N 083.34W 2468 < 10 R D E 50.42 12.94 14.29 5.65 10.32 2.50 .13 2.32 .19 98.76 890 SC
03.20N 083.34W 2468 < 10 R D E 52.11 12.90 14.33 5.35 10.19 2.59 .14 2,30 .22 100,13 889 SC
03.20N 083.34W 2468 < 10 R D E 51.32 13.08 14.39 5.54 10.32 2.53 .15 2.26 .20 99.79 888 SC
05.75N 082.87W 30g7 S 9 R 84 I 50.22 15.25 9.64 7.81 13.18 2.42 .05 1.19 .07 99.83 419 DP
PACIFIC OCEAN JUAN DE FUCA RIDGE SYSTEM
LAT. LONG. DEPTH AGE S T E SI02 AL203 FEO* MGO CAO NA20 K20 TI02 P205 SUM VG-* SO
42.50N 127.50W 2438 F D E 48.72 16.74 11.31 7.00 8.35 3.16 .94 1.81 ,29 98,32 322 US
42.50N 127,50W 2438 F D E 49,86 14,11 11,89 6.58 10.23 2.99 .18 2.15 .16 98.15 319 US
42.50N 127,50W 2438 F D E 49,63 16,72 12,32 7,49 7,96 2.79 .67 1.39 .20 99.17 320 US
42.50N 127.50W 2438 - F D E 49.69 16.41 12.34 7.30 8,05 2.78 .67 1,44 .24 98.92 324 US
42.50N 127.50W 2438 F D E 49.20 16,48 12,36 7,43 8,07 2,82 ,63 1,40 ,22 98.61 325 US
42.50N 127.50W 2438 F D E 49.63 16.42 12.41 7.30 8.03 2.83 .65 1.44 .22 98.93 323 US
42.50N 127,50W 2438 F D E 50,02 16.25 12.44 7.26 8.20 2.87 .68 1.43 ,23 99,38 317 US
42.50N 127.50W 2438 - F D E 49.36 16.57 12.45 7.54 7.92 2.78 .63 1.39 .22 98.86 316 US
42.50N 127.50W 2438 - F D E 49,81 16,40 12,48 7,23 7.94 2.88 .69 1.52 .24 99.19 318 US
42.50N 127,50W 2438 F D E 49,80 16.79 12.49 7.57 8.06 2.82 .63 1.39 .22 99.77 326 US
42.50N 127.50w 2438 F D E 50.42 15.31 12.94 7.58 8.75 2.49 ,21 1,51 ,12 99,33 321 US
44.17N 130.42W 2560 < 10 R D E 49,05 16,24 10,50 7,98 11.08 2.69 .15 1.35 .12 99,16 392 US
44.17N 130.42W 2560 < 10 R D E 50.49 15.39 10.98 6.61 11.40 2.89 ,27 2.05 .17 100,25 171 US
44.17N 130,42W 2560 < 10 R D E 49,9l 16,42 12.79 8,25 9,09 2.65 .09 1.39 .09 100.68 390 US
44.17N 130.42W 2560 < 10 R D E 49.48 16.66 12.79 8.25 9.14 2.70 .12 1.39 .08 100.61 391 US
44.18N 129.33W 335* < 10 R D E 51.01 15.02 10.86 6.77 10.21 2.77 .20 1.82 .12 98.78 785 CR
44.18N 129,33W 335* < 10 R D E 51.05 15,29 11.02 6.87 10.28 2.81 .20 1.95 .15 99.62 781 CR
44.18N 129.33W 335* < 10 R D E 50.43 14.72 11.04 7.09 10.40 2.80 .19 1.92 .16 98,75 786 CR
44.18N 129.33w 335* < 10 R Q E 50.53 14.90 11.05 6.81 10.26 2.77 .17 1.89 .15 98.53 782 CR
44.18N 129.33W 3354 < 10 R D E 50.25 15.15 11.07 7.07 10.36 2.82 .20 1.98 .18 99.08 784 CR
44.18N 129.33W 3354 < 10 R D E 51,35 14,72 11,21 6.79 10.32 2.86 .18 1.96 .21 99.60 783 CR
54 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
PACIFIC OCEAN JUAN DE FUCA RIDGE SYSTEM
LAT. LONG. DEPTH AGE S T E 5102 AL2O3 FEO* MGO CAO NA20 K20 TI02 P205 SUM VG-# SO
44.UN 129.33W 335* < 10 R D E 50.96 14.73 11.22 6.48 10.53 2.90 .20 2.00 .18 99.20 787 CR
44.25N 129.83W 2655 < 10 R D E 50.39 12.88 10.75 5.58 13.36 2.86 .15 2.89 ,22 99.08 329 US
44.25N 129.83W 2655 < 10 R D E 49.64 15.97 10.94 7.94 11,37 2.69 .16 1.64 .14 100.49 181 US
44.25N 129.83W 2655 < 10 R D E 49.60 16.24 11.11 8.02 11.58 2.59 .19 1.60 .15 101.08 179 US
44.25N 129.83W 2655 < 10 R D E 49.56 16.01 11.23 7.43 11.11 2.74 .23 1.81 .13 100.25 182 US
44.25N 129.83W 2655 < 10 R D E 48.91 16.08 11.33 7.99 10.98 2.65 .20 1.74 ,15 100.03 177 US
44.25N 129.83W 2655 < 10 R D E 49.41 14.76 11.50 7.45 10.46 2.91 .29 2.19 .22 99.19 333 US
44.25N 129.83W 2655 < 10 R D E 48.55 16.25 11.92 7.59 10.15 2.65 ,16 1.56 .12 98.95 334 US
44.25N 129.83W 2655 < 10 R D E 49.78 15.88 12.03 7.96 10.58 2.70 .19 1.81 .15 101.08 361 US
44.25N 129.83W 2655 < 10 R D E 49.95 15.37 12.11 6.80 9.77 2.85 .27 1.96 .15 99.23 336 US
44.25N 129.83W 2655 < 10 R D E 50.16 15.13 12.40 7.39 9.73 2.59 .26 1.90 .19 99.75 335 US
44.27N 129.75W 3995 < 10 F D E 49.41 16.67 9.77 8.23 11.77 2.68 .10 1.42 .12 100.17 173 US
44.27N 129.75W 3995 < 10 F D E 49.68 15.46 10.07 7.23 11.30 2.78 .28 1.95 .19 98.94 379 US
44.27N 129.75W 3995 < 10 F D E 49.36 15.29 10.24 7.16 11.36 2.91 ,30 1.91 .19 98.72 376 US
44.27N 129.75W 3995 < 10 F D E 47.53 17.61 10.27 8.82 11.67 2.44 .08 .82 .07 99.31 377 US
44.27N 129.75W 3995 < 10 F D E 48.14 18.08 10.63 8.78 11.71 2.44 ,06 .79 .04 100.67 373 US
44.27N 129.75W 3995 < 10 F D E 50.51 14.85 10.80 7.51 11.64 2.20 ,06 1.23 .08 98.88 369 US
44.27N 129.75W 3995 < 10 F D E 50.83 14.98 10.88 7.46 11.63 2.17 .06 1.21 .09 99.31 370 US
44.27N 129.75W 3995 < 10 f Q E 50.37 14.69 11.02 7.95 11.36 2.26 .07 1.23 .10 99.05 368 US
44.27N 129.75W 3995 < 10 F D E 49.00 15.60 11.04 7.12 10.84 2.97 .28 2.15 .18 99.18 172 US
44.27N 129.75W 3995 < 10 F D E 50.35 16.23 11.05 6.60 11.32 2.93 .28 2.08 .16 101.00 169 US
44.27N 129.75W 3995 < 10 F D E 50.15 14.73 11.08 6.56 11.27 2.98 ,39 2.54 .29 99.99 360 US
44.27N 129.75W 3995 < 10 F D E 49.76 14.73 11.14 6.88 10.58 3.06 .35 2,23 ,25 98.98 351 US
44.27N 129,75W 3995 < 10 F D E 50,89 14.68 11,16 7,66 11,52 2.21 .07 1.28 .07 99.54 371 US
44.27N 129.75W 3995 < 10 F D E 48.82 14.67 11.23 7.44 10.55 3.02 .32 2.27 .19 98.51 380 US
44.27N 129.75W 3995 < 10 F D E 50.09 15.20 11.24 6.78 10.47 2.98 .37 2.15 .23 99.51 357 US
44.27N 129.75W 3995 < 10 F D E 48.96 14.70 11.24 7.57 10.52 2.98 .31 2.24 .22 98.74 375 US
44.27N 129.75W 3995 < 10 F D E 49.05 14.73 11.27 7.47 10.64 2.87 .31 2.20 .21 98.75 374 US
44.27N 129.75W 3995 < 10 F D E 49.64 14,96 11,32 7,49 10,54 2,87 .30 2.16 .22 99.50 358 US
44.27N 129.75W 3995 < 10 F 0 E 49.21 14.80 11.34 7.21 10.50 3.09 .31 2.22 .23 98.91 381 US
44.27N 129.75W 3995 < 10 F D E 49.98 16.35 11,40 6.56 10.66 2.94 .37 2.21 .21 100.68 170 US
44.27N 129.75W 3995 < 10 F D E 49.29 14.86 11.42 7.30 10,60 2.94 .30 2.23 .21 99.15 346 US
44.27N 129.75W 3995 < 10 F D E 50,35 14.86 11.43 7.60 10.92 2.88 .31 2.21 .20 100.76 383 US
44.27N 129.75W 3995 < 10 F 0 E 49.92 15.46 11.44 7.42 10.58 2.98 ,30 2,15 ,22 100,47 382 US
44.27N 129.75W 3995 < 10 F D E 49.51 15.15 11.45 6.89 10.49 2.94 .30 2.21 .22 99.16 355 US
NUMBER 19 55
PACIFIC OCEAN JUAN DE FUCA RIDGE SYSTEM
LAT. LONG. DEPTH AGE S T E SIO2 AL2O3 FEO* MGO CAO NA2O K2C TIO2 P2O5 SUM VG-# SO
44.27N 129.75W 39y5 < 10 F D E 50.25 15.00 11.51 7.15 10.57 3.00 .34 2.19 .21 100.22 384 US
44.27N 129,75W 3995 < 10 F D E 49.95 14.82 11.52 7,13 10.68 3.03 ,33 2,26 .22 99,94 372 US
44.27N 129.75W 3995 < 10 F D E 49.15 15,43 11.70 7.28 10.42 3.11 ,29 2.26 ,22 99.86 178 US
44.27N 129.75W 3995 < 10 F D E 48.93 15.61 11.74 8,16 10.28 2.70 .20 1.73 .13 99.48 340 US
44.27N 129.75W 3995 < 10 F D E 49.37 14.67 11.74 6.85 10.17 3.17 .39 2.62 .29 99.27 378 US
44.27N 129.75W 3995 < 10 F D E 48.94 15.59 11.80 7.93 10,44 2.63 .20 1.74 .14 99.41 338 US
44.27N 129.75W 3995 < 10 F D E 49.53 15.37 11.81 7.21 9.99 2.77 .24 1,81 ,17 98,90 352 US
44.27N 129.75W 3995 < 10 F D E 50.99 15.18 11.83 7,87 10.41 2.81 .25 1.93 .15 101.42 387 US
44.27N 129.75W 3995 < 10 F D E 49.71 15,63 11,84 7,24 9,96 2.95 .25 1.93 .16 99.67 350 US
44.27N 129.75W 3995 < 10 F D E 49.01 15.41 11.89 7.88 10.42 2.71 .20 1.79 .15 99.46 339 US
44.27N 129.75W 3995 < 10 F D E 48.66 16.43 11.94 7.78 10.34 2.66 ,17 1,57 ,14 99.69 343 US
44.27N 129.75W 3995 < 10 F D E 50.09 15.24 11.94 7.38 10.16 3.03 .19 1.99 .17 100,19 356 US
44.27N 129,75W 3995 < 10 F D E 49.67 16.45 11.97 7.88 9,95 2.69 .15 1.31 .09 100.16 354 US
44.27N 129.75W 3995 < 10 F D E 49.51 16.87 11.97 8.07 9.99 2.69 ,12 1,22 ,07 100,51 385 US
44.27N 129.75W 3995 < 10 F D E 49.54 16.76 12.00 8.20 9.82 2.65 .10 1.26 ,09 100.42 344 US
44.27N 129.75W 3995 < 10 F D E 49.11 16.51 12.01 8.14 9.76 2.66 .13 1.23 .08 99.63 341 US
44.27N 129.75W 3995 < 10 F D E 49.12 16.35 12.04 7.61 10,36 2.70 .17 1,58 ,13 100,06 349 US
44.27N 129.75W 3995 < 10 F D E 48.86 16.33 12.07 7.50 10.17 2.67 .15 1.54 .13 99.42 332 US
44.27N 129.75W 3995 < 10 F D E 49.02 15.75 12.13 7.88 10.08 2.64 .18 1.60 .12 99,40 337 US
44.27N 129.75W 3995 < 10 F D E 48.24 16.89 12.17 7.10 9.76 2.47 ,14 1.38 .10 98.25 353 US
44.27N 129.75W 3995 < 10 F D E 50,18 15.62 12.20 7.53 9.71 2.72 .24 1,87 ,17 100,24 386 US
44.27N 129.75W 3995 < 10 F D E 49.36 16.53 12.23 7.63 10.27 2.70 .16 1.53 .14 100.55 347 US
44.27N 129.75W 3995 < 10 F D E 50.42 14.98 12.26 6.96 10.28 2.70 .24 1.95 ,17 99,96 359 US
44.27N 129.75W 3995 < 10 F D E 49.01 16.35 12.31 8.16 9.50 2.68 .13 1.47 ,14 99,75 342 US
44.27N 129.75W 3995 < 10 F D E 48.34 17.56 12.42 8.80 9.71 2.37 .06 .83 .06 100.15 348 US
44.27N 129.75W 3995 < 10 F D E 49.55 16.27 12.57 8.04 8.98 2.65 .10 1.38 .10 99.64 345 US
44.33N 129.75W 3445 < 10 F D E 49.95 16.19 9.67 7.04 11.43 2.91 .10 1.31 .09 98.69 082 US
44.33N 129.75W 3445 < 10 F D E 49.62 16.25 10.17 7.56 11.15 2.65 .10 1.39 .10 98.99 185 US
44.33N 129,75W 3*45 < 10 F D E 51,00 15.76 10.64 8.14 9.85 2.74 .11 1.52 ,09 99,85 080 US
44.33N 129.75W 3445 < 10 F D E 51.10 15.33 10,69 8.40 10,05 2.70 .12 1.47 .11 99.97 084 US
44.33N 129.75W 3445 < 10 F D E 51.02 15.20 10,72 8,35 10.23 2.55 .10 1.50 ,09 99,76 077 US
44.33N 129.75W 3445 < 10 F D E 50.76 15.28 10.75 8.38 10.08 2.60 .14 1.43 .11 99.53 017 US
44.33N 129.75W 3445 < 10 F D E 50.85 15.41 10.75 8.37 9.86 2.73 .12 1.53 .11 99.73 079 US
44.33N 129.75W 3445 < 10 F D E 50.89 15.79 10.78 7.89 10.12 2.78 .12 1.46 .12 99.95 083 US
44.33N 129.75W 3445 < 10 F D E 50.95 15.33 10.90 8.40 9.91 2.62 .12 1.50 .11 99.84 081 US
44.33N 129.75W 3445 < 10 F D E 51.19 15.45 10.94 8.43 10.43 2.73 .11 1.50 .10 100.88 086 US
56 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
OCEAN JuAN &E FUCA RIQGE SYSTEM
LAT. LONG. DEPTH AGE S T E SI02 AL2O3 FEO* MGO CAO NA20 K20 TI02 P2O5 SUM VG-# SO
44.33N 129.75W 3445 < 10 F D E 50.83 15.61 10.98 8.14 10.19 2.71 .13 1.47 .11 100.17 078 US
44.33N 129.83W 3140 < 10 F D E 50.82 14.11 12.08 6.71 11.77 2.69 .13 1.95 .14 100.40 184 US
44.33N 129.92w 4392 < 10 F D E 51.11 13.34 11.36 5.85 13.54 2.54 ,22 2.85 .23 101.04 388 US
44.33N 129.92W 4392 < 10 F D E 49.85 13.48 11.79 5.87 12.33 2.64 .17 2.38 .18 98.69 328 US
44.33N 129.92W 4392 < 10 F 0 E 50.76 13.87 11.89 6.13 11.96 2.65 .20 2.23 .17 99.86 389 US
44.33N 129.92W 4392 < 10 F D E 49.98 13.37 14.35 5.78 10.36 2.69 .24 2.79 .21 99.77 168 US
44.33N 129.92W 4392 < 10 F D E 50.01 13.31 14.67 5.63 10.50 2.80 .26 2.74 .22 100.14 180 US
44.40N 130.30W 3126 < 10 R 0 E 50.84 12.85 15.17 5.00 10.15 2.72 ,21 2.87 .26 100.07 780 CR
44.42N 129.92W 3084 < 10 F D E 50.74 14.10 11.98 6.52 12.37 2.71 .31 2.33 .17 101.23 327 US
44.42N 129.92W 3084 < 10 F D E 50.76 13.81 12.15 6.72 11.33 2.44 .14 1.94 .16 99.45 160 US
44.42N 129.92W 30s4 < 10 F D E 49.62 16.61 12.26 7.61 7.99 2,80 ,66 1.43 .22 99.20 315 US
44.42N 129.92W 3084 < 10 F D E 50.55 13.82 12.80 6.34 11.12 2.62 .16 2.11 .21 99.73 186 US
44.42N 129.92W 3084 < 10 F D E 50.17 13.48 12.99 6.21 10.96 2.69 .18 2.33 .17 99.18 187 US
44.42N 129.92W 3084 < 10 F D E 50.40 13.80 13.47 6.12 11,01 2.69 ,16 2,24 ,17 100,06 167 US
44.42N 129,92W 3084 < 10 F D E 50.18 13.62 13.51 6.12 11.06 2.72 ,16 2,28 ,14 99.79 183 US
44.42N 129.92W 3084 < 10 F D E 49.96 13.45 13.91 5.79 10.54 2.76 .17 2.59 .21 99.38 174 US
44.66N 130.33W 2220 < 1 R D E 50.35 14.52 10.96 7.31 12.21 2.45 ,l? 1.60 .12 99.64 044 US
44.66N 130.33W 2220 < 1 R D E 50.07 14.71 10.98 7.20 12.06 2.62 .09 1.65 .14 99.52 107 US
44.66N 130.33W 2220 < 1 R D E 50.58 14.60 10.99 7.40 12.07 2.42 .12 1.59 .11 99.88 043 US
44.66N 130.33W 2220 < 1 R D E 50.85 14.59 10.99 7.42 12.14 2.50 ,08 1.57 .11 100,25 163 US
44.66N 130.33W 2220 < 1 R D E 50.51 14.50 11.01 7.33 12.04 2.42 .13 1.55 .12 99.61 020 US
44.66N 130.33W 2220 < 1 R D E 50.06 14.71 11.02 7.30 12.06 2.42 .10 1.56 .14 99.37 016 US
44.66N 130.33W 2220 < 1 R D E 50.09 14.63 11.06 7.39 12.29 2.45 .12 1.59 .12 99.74 026 US
44.66N 130.33W 2220 < 1 R D E 50.11 14.71 11.06 7.45 12.11 2.51 .10 1.63 .13 99.81 033 US
44.66N 130.33W 2220 < 1 R D E 50.52 14.64 11.08 7.37 12.02 2.44 .10 1.60 .12 99.89 089 US
44.66N 130.33W 2220 < 1 R D E 50.60 14.73 11.13 7.39 12.21 2.43 .13 1.62 .12 100.36 025 US
44.66N 130.33W 2220 < 1 R 0 E 50.42 14.01 11.76 6.58 10.97 2.62 .19 1.80 .17 98.52 130 US
44.66N 130.33W 2220 < 1 R D E 50.56 13.88 11.77 6.58 10.96 2.68 .19 1.79 .18 98.59 68 US
44.66N 130.33W 2220 < 1 R D E 50.70 13.86 11.79 6.70 10.85 2.60 .19 1.83 .16 98.68 142 US
44.66N 130.33W 2220 < 1 R D E 49.79 13.81 11.85 6.63 10.94 2.59 .19 1.84 .17 97.81 141 US
44.66N 130.33W 2220 < 1 R D E 50.40 14.11 11.86 7.10 11.11 2.54 .18 1.77 .19 99.26 048 US
44.66N 130.33W 2220 < 1 R D E 50.35 14.18 11.86 6.20 11.21 2.59 .19 1.83 .16 98.57 125 US
44.66N 130.33W 2220 < 1 R D E 50.63 14.27 11.87 6.62 11.10 2.77 .18 1.85 .18 99.47 114 US
44.66N 130.33W 2220 < 1 R D E 50.28 14.10 11.87 6.54 11.02 2.60 ,18 1,86 ,19 98.64 123 US
44.66N 130.33W 2220 < 1 R D E 50.17 14.07 11.88 6.63 10.97 2.63 .18 1.82 .16 98.51 158 US
44.66N 130.33W 2220 < 1 R D E 50.35 14.66 10.89 7.24 12.16 2.55 .09 1.62 .11 99.67 159 US
NUMBER 19 57
PACIFIC OCEAN JUAN DE FUCA RIDGE SYSTEM
LAT, LONG. DEPTH AGE S T E SIO2 AL2O3 FEO* MGO CAO NA2O K2O TIO2 P2O5 SUM VG-# SO
44.66N 130.33W 2220 < 1 R D E 50.65 14.23 11.90 6.18 11.24 2.65 .19 1.91 .15 99.10 118 US
44.66N 130.33W 2220 < 1 R D E 50.73 14.15 11.91 6.63 11.04 2.60 .17 1.82 .18 99.23 056 US
44.66N 130.33W 2220 < 1 R D E 50.53 13.99 11.92 6.58 11.01 2.58 .19 1.82 .17 98.79 71 US
44.66N 130.33W 2220 < 1 R D E 50.74 14.19 11.92 6.71 10.90 2.72 .22 1.93 .20 99.53 098 US
44.66N 130.33W 2220 < 1 R D E 50.62 13.97 11.94 6.55 11.04 2.67 .18 1.80 .20 98.97 66 US
44.66N 130.33W 2220 < 1 R D E 51.28 14.05 11.94 6.69 10,94 2.56 .19 1.82 ,17 99.64 137 US
44.66N 130.33W 2220 < 1 R D E 51.08 14.48 11.94 6.15 11.28 2.67 .20 1.86 .16 99.82 156 US
44.66N 130.33W 2220 < 1 R D E 50.49 14.09 11.95 6.74 11.21 2.61 .19 1.83 .17 99.28 099 US
44.66N 130.33W 2220 < 1 R D E 50.77 14.04 11,96 6,73 11,08 2,67 .18 1.82 .16 99.41 153 US
44.66N 130.33W 2220 < 1 R D E 50.74 14.47 11.97 6.19 11.18 2.77 .19 1.89 .20 99.60 122 US
44.66N 130,33W 2220 < 1 R D E 50.26 14.03 11.98 6.68 11.11 2.66 .20 1.84 .18 98.94 053 US
44.66N 130.33W 2220 < 1 R D E 50.04 14.26 11.98 6.78 11.08 2.55 .19 1.85 .17 98.90 108 US
44.66N 130,33W 2220 < 1 R D E 50,10 14.05 11.99 6.68 11.35 2.59 .21 1.87 .17 99.01 109 US
44.66N 130.33W 2220 < 1 R D E 50.44 14.15 11.99 6.59 11.32 2.63 .17 1.84 .15 99.28 116 US
44.66N 130,33W 2220 < 1 R D E 50.42 13.95 11.99 6.65 10.90 2.62 .19 1.87 .17 98.76 133 US
44.66N 130,33W 2220 < 1 R D E 50.16 13.97 12.00 6.54 11.31 2.53 .14 1.92 ,16 98,73 021 US
44.66N 130,33W 2220 < 1 R D E 50,80 14,12 12,00 6.72 11,07 2.56 .19 1.85 .18 99.49 60 US
44.66N 130.33W 2220 < 1 R D E 50.73 14.05 12.00 6.18 11.24 2.69 .20 1.92 .16 99.17 134 US
44.66N 130.33W 2220 < 1 R D E 50.41 14.34 12.01 6.70 11.23 2.59 .20 1.90 .18 99.56 112 US
44.66N 130.33W 2220 < 1 R D E 50.35 13.79 12.01 6.74 11.26 2.42 .15 1.96 .14 98.82 126 US
44.66N 130.33W 2220 < 1 R D E 50,29 14,14 12,02 6.88 11.13 2.66 .17 1.85 .15 99.29 049 US
44.66N 130.33W 2220 < 1 R D E 50.44 13.80 12.02 6.67 11.25 2.41 .15 1.96 .12 98.82 129 US
44.66N 130.33W 2220 < 1 R D E 50.24 13*67 12.02 6*76 11.21 2.48 .16 1.91 .13 98.58 132 US
44.66N 130,33W 2220 < 1 R D E 50,58 13,97 12.04 6.68 10.92 2.62 .19 1.87 .16 99.03 050 US
44.66N 130,33W 2220 < 1 R D E 50,67 13,97 12,04 6.74 10.91 2.68 .21 1.81 .19 99.22 052 US
44.66N 130.33W 2220 < 1 R D E 50.90 14.06 12.05 6.58 11.01 2.70 .19 1.86 .19 99.54 58 US
44.66N 130.33W 2220 < 1 R D E 49.83 13.83 12.05 6.73 11.24 2.47 .16 1.89 .13 98.33 131 US
44.66N 130,33w 2220 < 1 R D E 50,84 14,00 12.06 6.72 10.97 2.60 .21 1.82 .19 99.41 051 US
44.66N 130.33W 2220 < 1 R D E 50.55 14.61 12.06 6.82 11,29 2,50 ,14 1,91 ,14 100,02 154 US
44.66N 130,33W 2220 < 1 R D E 50.72 14.05 12.07 6.69 11.03 2.70 .19 1.81 .16 99.42 62 US
44.66N 130.33W 2220 < 1 R D E 50.23 13.74 12.07 6.65 11.26 2.42 .15 1.96 .16 98.64 127 US
44.66N 130.33W 2220 < 1 R D E 50.25 14.05 12.07 6.06 11.27 2.62 ,22 1,92 ,19 98.65 140 US
44.66N 130.33w 2220 < 1 R D E 50,33 13.92 12.07 6.60 11.32 2.49 .13 1.97 .14 98.97 150 ljS
44.66N 130.33W 2220 < 1 R D E 50.24 15.76 12.08 6.82 11.29 2.48 .16 1.93 .15 100.91 121 US
44.66N 130.33W 2220 < 1 R D E 50.74 14.09 12.10 6.71 11.10 2.57 ,20 1,84 ,17 99,52 136 US
44.66N 130.33W 2220 < 1 R D E 50.58 13.94 12.12 6.83 11.32 2.41 .14 1.92 .15 99.41 042 US
58 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
PACIFIC OCEAN JUAN DE FUCA RIDGE SYSTEM
LAT. LONG, DEPTH AGE S T E SI02 AL2O3 FEO* MGO CAO NA2O K20 TI02 P2O5 SUM VG-# SO
44.66N 130,33W 2220 < 1 R D E 50.51 14.01 12.12 6.70 11.00 2.56 ,21 1,85 ,17 99,13 57 US
44.66N 130,33W 2220 < 1 R D E 50,26 14,06 12,12 6,40 11,42 2,44 .16 1.96 .13 98,95 144 US
44.66N 130.33W 2220 < 1 R D E 50.37 13.89 12.12 6.13 11.43 2.44 ,15 1,96 ,15 98,64 148 US
44.66N 130.33W 2220 < 1 R D E 51.22 14.05 12.12 6.61 11.03 2.64 .19 1.87 .16 99.89 155 US
44.66N 130.33W 2220 < 1 R D E 50.97 14,44 12.13 6.56 11.29 2.71 ,20 1,91 ,15 100,36 092 US
44.66N 130.33W 2220 < 1 R D E 50.70 14.11 12.13 6.23 11.71 2.65 .22 1.95 ,18 99.88 095 US
44.66N 130.33W 2220 < 1 R D E 51,14 13.63 12.13 6.78 11.19 2,49 .16 1.96 .14 99.62 139 US
44.66N 130.33W 2220 < 1 R D E 50,49 13.79 12.14 6.80 11.41 2.53 .14 1.94 .13 99.37 037 US
44.66N 130.33W 2220 < 1 R D E 50.83 13.85 12.14 6.47 11.01 2.59 .22 1.81 .21 99.13 67 US
44.66N 130.33W 2220 < 1 R D E 50.23 14.06 12.14 6.64 11.14 2.50 ,16 1.94 ,12 98.93 120 US
44.66N 130,33W 2220 < 1 R D E 50.40 14,08 12.15 6.94 11.56 2.61 .14 1.87 .12 99.87 029 US
44.66N 130,33W 2220 < 1 R D E 50.79 14.14 12.15 6.81 11.01 2.58 .20 1.82 .16 99.66 047 US
44.66N 130.33w 2220 < 1 R D E 49.57 14.17 12.15 6.49 11.78 2.57 .15 1.95 .14 98.97 110 US
44.66N 130.33W 2220 < 1 R D E 50.88 14.18 12.16 6.62 11.30 2.54 .21 1.90 .20 99.99 055 US
44.66N 130,33W 2220 < 1 R D E 50,81 14,10 12,16 6,77 11,39 2,68 ,18 1,88 ,15 100,12 076 US
44.66N 130.33W 2220 < 1 R D E 50.96 14.33 12.17 6.27 11.44 2.72 ,19 1.90 ,17 100,15 113 US
44.66N 130.33W 2220 < 1 R D E 50.87 14.10 12.18 6.90 11.41 2.53 .15 1.81 .13 100,08 031 US
44.66N 130,33W 2220 < 1 R 0 E 50,93 14.31 12.18 6.67 10.87 2.67 .19 1.91 ,18 99,91 096 US
44.66N 130.33W 2220 < 1 R D E 50.63 13.80 12,18 6,90 11.21 2,49 ,15 1.92 .14 99.42 138 US
44.66N 130,33W 2220 < 1 R D E 50,30 13.89 12.19 6.74 11.16 2.41 .15 1.96 .18 98.98 019 US
44.66N 130.33W 2220 < 1 R D E 50,57 14.47 12.19 6.59 11.05 2,61 ,21 1.86 .16 99.71 105 US
44.66N 130,33W 2220 < 1 R D E 50,07 14,11 12.19 6.22 12,09 2,61 .17 1.86 .18 99.50 117 US
44.66N 130,33W 2220 < 1 R D E 50,13 13.97 12.20 6.77 11,29 2.67 ,13 1,83 .12 99.11 018 US
44.66N 130,33W 2220 < 1 R D E 50,48 13.94 12,20 6.91 11.44 2.41 .15 2.00 .16 99.69 028 US
44.66N 130.33W 2220 < 1 R D E 50.64 14.15 12.20 6.68 11.23 2.72 ,21 1.82 ,16 99,81 097 US
44.66N 130,33W 2220 < 1 R D E 50.02 14.03 12,20 6,75 11,15 2,51 ,15 1.93 .16 98.90 103 US
44.66N 130.33W 2220 < 1 R D E 50.72 13.90 12.22 6.69 11.25 2.47 .14 1.92 .14 99.45 161 US
44.66N 130.33W 2220 < 1 R D E 50.54 13.98 12.22 6.72 11.34 2.51 .15 1.94 .14 99.54 166 US
44.66N 130.33W 2220 < 1 R D E 50.89 13.96 12.21 6.61 11,20 2.58 .20 1.85 .17 99.67 65 US
44.66N 130,33W 2220 < 1 R D E 51,14 14,32 12.21 6,43 11,14 2,80 ,20 1,91 ,17 100,32 093 US
44.66N 130,33W 2220 < 1 R D E 50.42 14.19 12.21 6.55 11.07 2.63 .20 I.87 .16 99.30 102 US
44.66N 130.33W 2220 < 1 R D E 50,39 13.98 12,21 6.69 11.45 2.55 ,17 1.78 .13 99.35 115 US
44.66N 130.33W 2220 < 1 R D E 50.05 13.92 12.22 6?82 11.32 2.49 .16 1.86 .15 98.99 041 US
44.66N 130.33W 2220 < 1 R D E 50.67 13.72 12.23 6.85 11.11 2.55 .16 1.94 .16 99.39 024 US
44.66N 130.33W 2220 < 1 R D E 50.67 14.22 12.23 6.86 11.55 2.60 ,14 1.88 .16 100.31 032 US
NUMBER 19 59
PACIFIC OCEAN JUAN DE FUCA RIDGE SYSTEM
LAT. LONG. DEPTH AGE S T E SIO2 AL2O3 FEO# MGO CAO NA20 K20 TIO2 P2O5 SUM VG-* SO
44.66N 130.33W 2220 < 1 R D E 50.57 13.96 12.23 6.92 11.39 2.38 .15 1.95 .13 99.68 040 US
44.66N 130.33w 2220 < 1 R D E 50.64 14.02 12.24 6.72 11.21 2.47 .15 1.88 .15 99.48 104 US
44.66N 130.33W 2220 < 1 R D E 50.45 14.41 12.24 6.63 11.50 2.64 .19 1.78 .17 100.01 111 US
44.66N 130.33W 2220 < 1 R D E 50.82 14.07 12.26 6.79 11.58 2.60 .13 1.83 .14 100.22 101 US
44.66N 130.33W 2220 < 1 R D E 49.93 13.84 12.27 6.9l 11.13 2.58 .14 1.82 .14 98.76 023 US
44.66N 130.33W 2220 < 1 R D E 50.43 13.85 12.27 6.81 11.31 2.53 .14 1.86 .14 99.34 038 US
44.66N 130.33W 2220 < 1 R D E 50.46 13.84 12.27 6.79 11.41 2.54 ,16 1.93 .16 99.56 088 US
44.66N 130.33W 2220 < 1 R D E 50.39 13.89 12.27 6.46 11.38 2.54 .15 1.97 .15 99.20 100 US
44.66N 130.33W 2220 < 1 R D E 51.18 14.17 12.27 6.58 10.92 2,66 .19 1.78 .16 99.91 135 US
44.66N 130.33W 2220 < 1 R D E 50.82 14.26 12.28 6.42 11.10 2.63 .20 1.83 .17 99.71 091 US
44.66N 130.33W 2220 < 1 R D E 50.93 14.01 12.28 6.73 11.38 2.52 .15 2.00 .15 100.15 124 US
44.66N 130.33W 2220 < 1 R D E 50.36 13.90 12.29 6.76 11.38 2.48 .14 1.87 ,15 99.33 094 US
44.66N 130.33W 2220 < 1 R D E 50.73 13.79 12.29 6.49 11.41 2.49 .15 1.96 .14 99.45 164 US
44.66N 130.33W 2220 < 1 R D E 50.08 13.90 12,31 5,89 10.61 2.79 .27 1.95 .25 98.05 119 US
44.66N 130.33W 2220 < 1 R D E 50.52 13.55 12.33 6.79 11.44 2.57 ,13 1.88 .11 99.32 152 US
44.66N 130,33W 2220 < 1 R D E 50.92 14.00 12.34 6.93 11.52 2,58 ,14 1,84 ,14 100,41 030 US
44.66N 130.33W 2220 < 1 R D E 50.69 14.16 12,34 6.58 11.05 2.60 .18 1.88 .16 99.64 165 US
44.66N 130.33W 2220 < 1 R D E 50.17 14.03 12.35 6.94 11.22 2.46 .15 1.84 .18 99.34 022 US
44.66N 130.33W 2220 < 1 R D E 50.77 14.16 12.36 6.90 11.38 2.58 .15 1.92 .19 100.41 027 US
44.66N 130.33W 2220 < 1 R D E 50.87 14.06 12.36 6.79 11.53 2.56 .14 1.93 .16 100.40 039 US
44.66N 130.33W 2220 < 1 R D E 51.31 13.99 12.36 6.82 11.71 2.57 .17 1.95 .14 101.02 087 US
44.66N 130,33W 2220 < 1 R D E 50.88 13.85 12.37 6.11 10,59 2,85 .27 2.04 .20 99.16 61 US
44.66N 130,33W 2220 < 1 R D E 50,51 13,89 12.39 6.84 11.17 2.50 ,14 2.00 ,12 99,56 090 US
44.66N 130.33W 2220 < 1 R D E 50.59 13.93 12,42 6,93 11,45 2,41 .14 1.89 .13 99.89 036 US
44.66N 130.33W 2220 < 1 R D E 50.65 14.02 12.42 6?82 11.56 2.57 .13 1.92 .15 100.24 045 US
44.66N 130,33W 2220 < 1 R D E 50.72 13.66 12.42 6.13 10.46 2.69 .26 2.00 ,21 98.55 128 US
44.66N 130.33W 2220 < 1 R D E 50.95 14.44 12.44 6.19 11,66 2.52 .14 2,01 ,18 100,53 106 US
44.66N 130,33w 2220 < 1 R D E 50,59 13,77 12,50 6,11 10,56 2,73 ,27 2,01 ,20 98.74 151 US
44.66N 130,33W 2220 < 1 R D E 50,70 14.07 12.50 6.45 11,32 2.50 .16 1,96 .16 99,82 157 US
44.66N 130,33W 2220 < 1 R D E 51.07 13.65 12.52 6.03 10.24 2.82 .27 1,96 ,27 98.83 054 US
44.66N 130.33W 2220 < 1 R D E 51.18 14.14 12.52 6.83 11.20 2.66 .19 1,87 ,18 100,77 075 US
44.66N 130,33w 2220 < 1 R D E 51.13 13.57 12,53 6,11 10,44 2.82 .25 1.98 .24 99.07 64 US
44.66N 130.33w 2220 < 1 R D E 51.02 14.03 12.54 6.85 11.54 2.49 .14 1.90 ,16 100,67 034 US
44.66N 130.33W 2220 < 1 R D E 50.86 13.70 12.55 6.17 10.46 2.77 ,25 1.98 .22 98.96 63 US
44.66N 130,33W 2220 < 1 R D E 50.38 13.86 12.59 6*65 11.37 2.39 .14 2.02 .16 99.56 015 US
44.66N 130,33W 2220 < 1 R D E 51,13 13.80 12.61 6.17 10.49 2.71 .27 1.98 .26 99.42 59 US
50 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
PACIFIC OCEAN JUAN DE FUCA RIDGE SYSTEM
LAT. LONG. DEPTH AGE S T E SI02 AL2O3 FED* MGO CAO NA2O K20 TI02 P205 SUM VG-* SO
44.66N 130.33W 2220 < 1 R D E 51.08 13.86 12.65 6.02 10.43 2.94 .28 2.04 .22 99.52 162 US
44.66N 130.33W 2220 < 1 R 0 E 51.17 13.74 12.66 5.87 10.42 2.80 .26 2.01 .21 99.14 145 US
44.66N 130.33W 2220 < 1 R D E 51.03 14.02 12.80 6.90 11.64 2.48 .15 1.95 .16 101.13 035 US
44.66N 130.33W 2220 < 1 R D E 51.40 13.76 13.07 6.25 10.22 2.89 .26 1.94 .25 100.04 012 US
44.66N 130.33W 2220 < 1 R D E 51.74 14.30 13.42 5.37 10.35 2.32 .62 2.26 .19 100.57 046 US
44.75N 130.42W 2600 < 10 R D E 50.93 13.36 14.21 5.88 10.81 2.63 .17 2.46 .16 100.61 175 US
44.75N 130.50W 2995 < 10 R Q E 50.65 14.11 12.52 6.56 11.63 2.48 .12 1.83 .12 100.02 176 US
46.09N 129.92W 2199 < 10 R D E 49.90 14.18 12.16 6.35 11.89 2.98 .21 1.86 .13 99.66 773 TH
46.12N 130.OOW 2744 < 10 R D E 48.90 14.33 13.17 5.71 10.95 3.29 .28 2.28 .24 99.15 771 TH
46.12N 130.OOW 2744 < 10 R D E 48.96 13.73 13.18 5.96 10.93 3.25 .23 2.26 .20 98.70 772 TH
46.12N 130.OOW 2744 < 10 R D E 49.97 13.79 13.24 5.79 10.85 3.30 .26 2.28 .21 99.69 770 TH
46.27N 129.60w 2649 < ,10 R D E 50.22 14.44 10.93 7.17 12.17 2.53 .05 1.34 .08 98.93 774 TH
46.27N 129.60W 2649 < 10 R D E 49.86 14.05 12.44 6.40 11.75 3.02 .20 1.84 .14 99.70 775 TH
46.39N 129.97W 2522 < 10 R D E 48.23 17.24 9.98 8.51 11.76 2.55 .05 1.06 .04 99.42 768 TH
46.39N 129.97W 2522 < 10 R D E 48.27 17.52 10.01 8.93 11.87 2.56 .02 1.19 .05 100.42 769 TH
The Harleton, Texas, Chondrite
Roy S. Clarke, Jr., Edward P. Henderson, and Brian Mason
ABSTRACT
The Harleton meteorite fell near Harleton, Texas(32?40.5'N, 94?30.7'W) on 30 May 1961. A single
stone, weighing 8.36 kg, was recovered. Chemicalanalyses and microscopic examination show that it
is an olivine-hypersthene chondrite (L6). Principalminerals are olivine and orthopyroxene, with minor
amounts of plagioclase, nickel-iron, and troilite, and
accessory chromite.
Introduction
The Harleton meteorite fell four miles [6 km]
east of Harleton, Harrison County, Texas, at 2230
(Central Time) on 30 May 1961, on the property of
J. J. and Bernice Craver; the coordinates of the
place of fall are 32?40.5'N, 94?30.7'W. A single
stone, weighing 8.36 kg, was recovered from a shal-
low crater in sandy ground within ten minutes of
the time of fall. An examination of that specimen
shows that other pieces were shed from it during
high velocity flight, but none was recovered. The
fireball accompanying the fall was seen over a
considerable area of east Texas; the meteorite was
traveling approximately west to east.
The Harleton meteorite was purchased from the
property owners by E. P. Henderson on 12 June
1961. Dr. Henderson represented both the Smith-
sonian Institution and an informal consortium of
interested institutions in this difficult negotiation.
The meteorite arrived at the National Museum of
Roy S. Clarke, Jr., Edward P. Henderson, and Brian Mason,
Department of Mineral Sciences, National Museum of Nat-
ural History, Smithsonian Institution, Washington, D.C.
20560.
Natural History in Washington on 13 June and a
mold for subsequent preparation of models was
made during the day of 14 June. Late that same
day the Harleton meteorite was broken in half in
a jaw crusher. One of the halves was broken down
into smaller pieces using the same technique. Most
of these fragments were distributed to scientific
colleagues for detailed studies on 15 June, just 16
days after the fall. Details of the various trans-
actions involved are in Smithsonian accession file
236677, and the meteorite has been assigned catalog
number USNM 2576.
The prompt recovery and distribution of the
Harleton meteorite made it a particularly inter-
esting specimen for the study of phenomena asso-
ciated with freshly fallen meteorites. Published
reports that discuss these results are listed here:
Bainbridge, Suess, and Wanke, 1962; Davis,
Stoenner, and Schaeffer, 1963; Eberhardt, et al.,
1966; Fireman, 1967; Fireman, DeFelice, and Tilles,
1963; Goel and Kohman, 1962; Honda and Arnold,
1964; Kohman and Goel, 1963; Mabuchi, et al.,
1968; Osborn, 1972; Rowe, Van Dilla, and
Anderson, 1963; Shedlovsky, Cressy, and Kohman,
1967; and Suess and Wanke, 1962.
ACKNOWLEDGMENTS.?We are indebted to a
group of scientific colleagues for providing funding
to help in the purchase of the Harleton meteorite.
Morphology
The stone is roughly cuboidal in form, 19 X
14 X 13 cm in maximum dimensions. The mor-
phology shows several significant features resulting
from ablation and spallation during its fall through
the atmosphere. These are shown in a series of
pictures taken of its various sides.
61
62 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
1. One side is quite flat and has a square outline
(Figure 1).
2. The fusion crust that covers the flat side has
different markings than the crust on the other
surfaces (Figure 2), yet its texture and thickness are
essentially the same as on the other sides.
3. Around the edges of this rear square face (Fig-
ure 1) there is a slight ridge, which is due to the
accumulation of overturned stringers of surface
material. Molten material was pushed backwards
on the side faces by the strong lateral flow, and
part of this was deposited as delicate stringers of
glass by the doughnut-shaped vortex trailing the
rear face. This vortex carried material outward
from the edges with the side faces, depositing it on
the rear face and moving it toward the edges. Thus
at the edges there was a mingling of two forces, the
stronger lateral flow off the sides of the meteorite
FIGURE 1.?Rear surface of the Harleton meteorite; maximum width of specimen, 14 cm.
NUMBER 19 63
FIGURE 2.?Side view of Harleton meteorite, showing flow lines on fusion crust;
maximum length of specimen, 21 cm.
64 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
and the slower-moving vortex pushing the molten
material from the rear face to the edge. Where these
forces met, a ridge formed around the rear face of a
falling orientated body.
4. The square face (Figure 1) is to some degree
ablated but less so than the other faces, and it has
totally different flight markings.
5. Since this side has a square outline it repre-
FIGURE 3.?Side view of Harleton meteorite, showing cuboidal form;
maximum length of specimen, 19 cm.
NUMBER 19 65
sents a break in the main mass late in the high-
velocity flight, but while the meteorite was still
falling fast enough to form fusion crust. The sharp
edges around this face have been only slightly
rounded, indicating a brief period of ablation.
6. This stone not only has an unusual flat square
face but also has other surfaces which are almost at
right angles to it (Figure 3). Thus there are three
rectilinear directions represented in the surfaces of
the meteorite.
7. The shape of this mass, therefore, shows that
the meteorite broke up during high-velocity flight.
After each break the object adjusted its position so
that its center of gravity and the stagnation point
on its front face were on the line of fall of the
meteorite. The weight of the object decreased by
spallation and ablation, and its velocity was
decreased to free-fall velocity by atmospheric
friction.
The morphology of this meteorite shows that
other fragments must have fallen as individual
stones along its trajectory. None was recovered,
however, probably because the brushy terrain made
search and sighting difficult.
Structure and Mineralogy
When viewed with the naked eye, a broken
surface of the meteorite appears remarkably homo-
geneous, the material being compact and pale
gray. With a hand lens brightly reflecting particles
of nickel-iron and troilite are seen dispersed
FIGURE 4.?Photomicrograph (reflected light) of a polished surface of the Harleton meteorite;
metal particles are white, troilite (and chromite) pale gray, silicates dark gray. Greatest dimen-
sion, 2,0 mm.
66 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
throughout, and chondrules are few and poorly
defined. These features are demonstrated by a low-
power photomicrograph of a polished surface (Fig-
ure 4). An unusual feature of broken surfaces of
this meteorite is the complete absence of any rusting
around the metal particles, despite exposure to the
atmosphere for many years; this implies the absence
of lawrencite. Only two thin sulfide veins were
observed on a 170 cm2 broken surface. One crossed
the specimen for 14 cm, while the other was only
3 cm long.
Thin sections under the microscope show a
granular aggregate of olivine, orthopyroxene, and
opaque minerals (Figure 5). The original chondritic
texture has almost disappeared. Chondrules are
recognizable by their vaguely circular form and
their usually coarser grain size than the surrounding
matrix. The fusion crust shows three well-
developed zones. The outermost zone is very thin,
averaging about 0.05 mm, and consists of black
opaque glass, the opacity appearing to be largely
due to finely dispersed magnitite or magnesioferrite.
The next zone averages 0.1 mm, is transparent, and
consists largely of granular olivine and pyroxene
like that in the body of the meteorite; it also
contains occasional pools of isotropic, fused plagio-
clase. The innermost zone is considerably thicker,
averaging 0.3 mm; it is black and opaque in trans-
mitted light, but in reflected light it is seen to
consist of the same minerals as the body of the
meteorite, but impregnated with a network of
minute troilite veinlets following grain boundaries,
cleavages, and fractures.
Reflected light examination of polished surfaces
revealed the presence of troilite, kamacite, taenite,
chromite, and trace amounts of copper. Troilite is
mainly present in isolated coarse-grained patches,
but also occurs in association with kamacite and/or
taenite. A variety of metal structures is seen on
etched surfaces. Large clear kamacite areas are
present, as are polycrystalline kamacite masses.
Some kamacite areas contain silicate inclusions and
several contain small troilites. Taenite inclusions
generally are smaller than kamacite and have com-
plex structures. They appear to be pearlitic and
occasionally include small grains of troilite. Small
areas of copper were observed twice within kama-
cite and in association with small grains of troilite,
and once at a grain boundary within a large area
of troilite. Several areas that suggest shock melting
of troilite or kamacite were observed, but these are
comparatively rare. The overall impression is one
of a compact rock with clean and well-defined
crystal boundaries.
As mentioned above, the principal minerals are
olivine and pyroxene. Other characteristic minerals
are nickel-iron, plagioclase, feldspar, and troilite.
Minor minerals include chromite and a phosphate
mineral (apatite and/or whitlockite) and copper is
present as a trace mineral. Ramdohr (1973:89) has
recorded the following opaque minerals: kamacite,
taenite, plessite, copper, troilite, chalcopyrrhotite
(trace), mackinawite, and chromite. Our notes on
some of the minerals follow.
Olivine: The refractive indices are a = 1.682,
y = 1.720, indicating a content of 25 mole percent
of the Fe2SiO4 component, according to the deter-
minative curve of Poldervaart (1950). Microprobe
analyses show 24.6 mole percent Fe2SiO4 in the oli-
vine. The chemical analysis of the acid-soluble
nonmagnetic fraction (Table 1), essentially olivine
with troilite and a little phosphate, indicates 26
mole percent Fe2SiO4.
Orthopyroxene: The refractive indices are a ?
1.678, y = 1.689, indicating a content of 21 mole
percent of the FeSiO3 component, according to the
determinative curve of Kuno (1954). Microprobe
analyses show the Fe/Fe + Mg mole percentage of
the orthopyroxene to be 22.4, with a content of
0.85% CaO in this material. The chemical analysis
of the acid-insoluble nonmagnetic fraction (Table
1), essentially orthopyroxene and plagioclase, shows
an Fe/Fe+Mg mole percentage of 23. In terms of
the conventional subdivision of meteoritic pyroxene,
this falls in the compositional range of hypersthene.
Diopside: An x-ray diffractogram of the acid-
insoluble fraction shows a low-intensity peak cor-
responding to diopside. This mineral was not
certainly identified microscopically or with the
microprobe, although some turbid and fine-grained
material is probably clinopyroxene.
Plagioclase: The plagioclase feldspar is fine-
grained, granular, untwinned, and interstitial to
the other minerals. Microprobe analyses give a
composition of An9, with a K2O content of 1.11%.
Chromite: Bunch, Keil, and Snetsinger (1967,
table 2) give the following microprobe analysis of
Harleton chromite: Cr2O3, 56.0; A12O3, 5.1; V2O3,
0.73; TiO2, 2.88; FeO, 33.4; MgO, 2.11; MnO, 0.57.
NUMBER 19 67
FIGURE 5.?Photomicrograph (transmitted light) of a thin section of the Harleton meteorite,
showing fusion crust on left; width of section, 1.8 mm.
68 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
Chemical Composition
Fragments of the meteorite free of fusion crust
were selected for chemical analysis (Table 1). They
were crushed to a fine powder containing a few
residual larger particles of metal. This material
was separated into magnetic and nonmagnetic frac-
tions, which were individually leached with 20%
HC1 in a nitrogen atmosphere. Sample solutions
containing the HCl-soluble magnetic fraction (I)
and the HCl-soluble nonmagnetic fraction (II) re-
TABLE 1.?Chemical analysis of the Harleton meteorite
Constituent
Fe (metal)
Ni
Co
FeS
SiO2
TiO2
A12O3
CroO?
FeO ..
MnO
MgO
CaO
Na20
K20
P205
H20(-)
Total
Total Fe
I II III Composite
72.4
11.3
0.61
2.99
4.57
3.2
<0.1
5.00
<0.2
100.06
76.8
<0.01
11.84
31.84
0.02
21.3
0.3933.35
0.59
0.48
99.8
24.1
57.51
0.21
5.10
10.5
0.34
19.82
3.65
2.2
0.3
<0.1
0.17
99.8
8.1
7.28
1.14
0.066.58*
39.85
0.10
2.14
0.52*
14.3 **
0.33
24.77
1.810.92
0.1
0.23
0.07
100.2
22.6
I = HCl-soluble magnetic fraction (10.05%of sample.)
II = HCl-soluble nonmagnetic fraction (47.86% of sample.)
Ill = Total acid-insoluble fractions (41.95% of sample.)
*S and Cr were determined on powder prepared from total
meteorite.
**Based on composite total Fe, direct S, and metallic Fe.
suited, along with acid-insoluble fractions that were
combined to form a separate sample (III). These
three samples were analyzed separately, the results
along with a composite analysis being given in
Table 1. The analytical procedures used were
mainly the well-known methods of Hillebrand,
et al. (1953) and Peck (1964).
The major elements were determined on aliquots
of solutions I and II, and on a solution resulting
from the fusion of a sample of the acid-insoluble
fraction (III) with Na2CO3. SiO2 was determined
gravimetrically by dehydration from perchloric acid
and volatilization with HF. The R2O3 group was
precipitated with NH4OH, ignited and weighed,
and dissolved and taken to volume in 10% H2SO4
after pyrosulfate fusion. No correction of SiO2
values was made for SiO2 present in the R2O3 pre-
cipitate. This was followed by precipitation of the
ammonium sulfide group. CaO was determined
gravimetrically by double precipitation of calcium
oxalate and ignition to CaO. MgO was determined
gravimetrically by double precipitation as Mg-
(NH4)PO4 and ignition to Mg2P2O7. Mn was deter-
mined in the Mg2P2O7 and found to be negligible.
Total Fe and A12O3 were determined on aliquots
of the R2O3 group solution. Fe was titrated with
K2Cr2O7 after reduction with silver. A12O3 was
determined gravimetrically with 8-hydroxyquinoline
from a tartrate-cyanide solution. Loveland, Schmitt,
and Fisher (1969), by neutron activation analysis,
found 1.21% Al in Harleton; this is equivalent to
2.19% A12O3, in excellent agreement with the gravi-
metric determination.
The following determinations were made on
separate aliquots of I and II, and samples of III.
TiO2 was determined spectrophotometrically with
tiron using the method of Rigg and Wagenbauer
(1961). Ni was determined gravimetrically with
dimethylglyoxime. MnO was determined spectro-
photometrically as MnO4-x using KIO4 as the
oxidant. P2O5 was determined spectrophotometri-
cally as the phosphomolybdate and Co with
nitroso-R, both as described as Moss, Hey, and
Bothwell (1961). The alkalis were determined
flame-photometrically (Grimaldi, 1960).
Cr and S were determined on a powder sample
prepared from fragments of the total meteorite,
fused with Na2CO3 and KNO3. Cr was determined^
spectrophotometrically as Cr2O7"2 on the leachate
from the fusion. The same solution was used for
the gravimetric determination of S as BaSO4.
FeS in I and II was calculated from the S value
determined by passing the gas evolved on solution
of the sample into lead acetate. The evolved H2S
was precipitated as PbS and converted to PbSO4
for a gravimetric determination of S. The FeS
figure used in the composite analysis was based on
the direct determination of S in the total meteorite.
FeO was calculated in III by assuming that all of
the iron was present as FeO. In II it was assumed
that all of the Fe present was in the form of FeO
with the exception of that combined with S. Thei
SiO2/MgO ratio in I was very close to that observed
in II. On this basis, it was assumed that the
FeO/SiO2 ratio in I would be the same as that ob*;
NUMBER 19 69
TABLE 2.?Normative composition of the Harleton meteorite in weight percent
Constituent
Olivine
Hypersthene
Diopside
Albite
Orthoclase
Weight percent
43.2
25.5
4.9
7.8
1.4
0.6
Constituent
Apatite
Chromite
Ilmenite
Troilite
Weight percent
0.5
0.8
0.2
6.6
8.5
served in II. This ratio was used to calculate the
FeO value for I. The FeO value for the composite
analysis was based on the total Fe, the direct S,
and the metallic Fe values. The metallic Fe value
in I was determined by correcting the total Fe value
in I for Fe combined as FeS and FeO.
The normative composition of the Harleton
meteorite, calculated from the analysis, is given in
Table 2. The figures are consistent with the
observed mineralogical composition. From the
analysis acid-soluble silicate, which is olivine,
amounts to approximately 42%, compared to 43.2%
in the norm; acid-insoluble silicate (pyroxene and
plagioclase) is 42%, and the norm shows 9.8%
plagioclase and 30.4% pyroxene.
The chemical and mineralogical composition of
the Harleton meteorite shows that it is a typical
olivine-hypersthene chondrite, according to the
classification of Prior (1920). The total iron content,
22.6%, is that of an L (low-iron) group chondrite
in the Urey-Craig classification (1953). Van Schmus
and Wood (1967:764) classify Harleton as an L6
chondrite.
Literature Cited
Bainbridge, A. E., H. E. Suess, and H. Wanke
1962. The Tritium Content of Three Stony Meteorites
and One Iron Meteorite. Geochimica et Cosmo-
chimica Ada, 26:471-473.
Bunch, T. E., Klaus Keil, and K. G. Snetsinger
1967. Chromite Composition in Relation to Chemistry
and Texture of Ordinary Chondrites. Geochimica et
Cosmochimica Ada, 31:1569-1582.
Davis, R., Jr., R. W. Stoenner, and O. A. Schaeffer
1963. Cosmic-Ray Produced Ar37 and Ar39 Activities in
Recently Fallen Meteorites. Pages 355-365 in Radio-
active Dating. Vienna: International Atomic Energy
Agency.
Eberhardt, P., O. Eugster, J. Geiss, and K. Marti
1966. Rare Gas Measurements in 30 Stone Meteorites.
Zeitschrift fur Naturforschung, 21a:414-^126.
Fireman, E. L.
1967. Radioactivities in Meteorites and Cosmic-Ray Varia-
tions. Geochimica et Cosmochimica Ada, 31:1691-
1700.
Fireman, E. L., J. DeFelice, and D. Tilles
1963. Tritium and Radioactive Argon and Xenon in
Meteorites and Satellites. Pages 323-334 in Radio-
active Dating. Vienna: International Atomic Energy
Agency.
Goel, Parmatma S., and Truman P. Kohman
1962. Cosmogenic Carbon-14 in Meteorites and Terrestrial
Ages of "Finds" and Craters. Science, 136:875-876.
Grimaldi, F. S.
1960. Dilution-Addition Method for Flame Spectropho-
tometry. U.S. Geological Survey Professional Paper,
400B:494-495.
Hillebrand, W. F., G. E. F. Lundell, H. A. Bright, and
J. I. Hoffman
1953. Applied Inorganic Analysis. 2nd edition, 1034 pages.
New York: John Wiley and Sons.
Honda, Masatake, and James R. Arnold
1964. Effects of Cosmic Rays on Meteorites. Science
, 143:203-212.
Kohman, T. P., and P. S. Goel
1963. Terrestrial Ages of Meteorites from Cosmogenic CM.
Pages 395-411 in Radioactive Dating. Vienna: In-
ternational Atomic Energy Agency.
Kuno, H.
1954. Study of Orthopyroxene from Volcanic Rocks. Amer-
ican Mineralogist, 39:30-46.
Loveland, W., R. A. Schmitt, and D. E. Fisher
1969. Aluminum Abundances in Stony Meteorites. Geo-
chimica et Cosmochimica Ada, 33:375-385.
Mabuchi. H., J. Tobailem, C. Leger, and R. Bibron
1968. Radioactivite induite par le rayonnement cosmique
dans la meteorite Granes. Geochimica et, Cosmo-
chimica Ada, 32:949-963.
Moss, A. A., M. H. Hey, and D. I. Bothwell
1961. Methods for the Chemical Analysis of Meteorites,
I: Siderites, Mineralogical Magazine, 32:802-816.
70 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
Osborn, T. W.
1972. Evidence for Association between Ir and Al in L
Chondrites. Nature Physical Science, 239:10-11.
Peck, L.
1964. Systematic Analysis of Silicates. U.S. Geological Sur-
vey Bulletin, 1170:1-89.
Poldervaart, A.
1950. Correlation of Physical Properties and Chemical
Composition in Plagioclase, Olivine, and Ortho-
pyroxene Series. American Mineralogist, 35:1067-
1079.
Prior, G. T.
1920. The Classification of Meteorites. Mineralogical
Magazine, 19:51-63.
Ramdohr, Paul
1973. The Opaque Minerals in Stony Meteorites. 244
Pages. Amsterdam: Elsevier Publishing Company.
Rigg, Tryson, and Heinrich A. Wagenbaur
1961. Spectrophotometric Determination of Titanium in
Silicate Rocks. Analytical Chemistry, 33:1347-1349.
Rowe, M. W., M. A. Van Dilla, and E. C. Anderson
1963. On the Radioactivity of Stone Meteorites. Geo-
chimica et Cosmochimica Ada, 27:983-1001.
Shedlovsky, Julian P., Philip J. Cressy, Jr., and Truman P.
Kohman
1967. Cosmogenic Radioactivities in the Peace River and
Harleton Chondrites. Journal of Geophysical Re-
search, 72:5051-5058.
Suess, H. E., and H. Wiinke
1962. Radiocarbon Contents and Terrestrial Age of
Twelve Stony Meteorites and One Iron Meteorite.
Geochimica et Cosmochimica Ada, 26:475-480.
Urey, H. C, and1 H. Craig
1953. The Classification of the Stone Meteorites and the
Origin of the Meteorites. Geochimica et Cosmo-
chimica Ada, 4:36-82.
Van Schmus. W. R., and J. A. Wood
1967. A Chemical and Petrologic Classification for the
Chondritic Meteorites. Geochimica et Cosmochimica
Ada, 31:747-765.
Eight L-Group Chondrites: A Comparative Study
Ananda Dube, Becky j. Fredriksson, Eugene Jaroseiuich, Joseph A. Nelen,
Albert F. Noonan, Jane O'Keefe, and Kurt Fredriksson
ABSTRACT
The bulk chemical compositions of eight L-groupchondrites, Atarra, Cranganore, Karkh, Kuttip-
puram, Mabwe-Khoywa, Mirzapur, Segowlie, andSultanpur, all falls and mostly from the collection
of the Geological Survey of India, Calcutta, have
been determined by classical wet chemical analysis.In addition, the compositions and abundances of
individual mineral phases were determined withelectron-probe techniques.
Seven of the eight stones represent the petro-graphic types 4, 5, and 6, while one, Mabwe-
Khoywa, cannot be classified because it is a poly-mict breccia. Still, the practically identical bulk
and phase compositions imply a similar (chemi-cally identical) parent; thus any metamorphic
recrystallization must have occurred before the
various fragments accreted. Therefore, we interpretthese L-group chondrites, in addition to four of the
H-group previously reported, as products of mul-tiple impacts of various intensities on similar mate-
rials if not on the same parent body.
Introduction
The eight hypersthene (L-group) chondrites, all
observed falls, described here were selected for
detailed studies because they represent wide ranges
in macroscopic texture, hardness, color, and visibil-
Ananda Dube, Geological Survey of India, Calcutta IB, India;
Becky J. Fredriksson, Eugene Jarosewich, Joseph A. Nelen,
Albert F. Noonan, and Kurt Fredriksson, Department of
Mineral Sciences, National Museum of Natural History,
Smithsonian Institution, Washington, D.C. 20360; Jane
O'Keefe, Geology Department, Rice University, Houston,
Texas 77001.
ity of chondrules. This is reflected to some degree in
their classifications by Hey (1966), Mason (1975),
and Wasson (1974). Two are black chondrites, L4
and L6 respectively; two are gray chondrites, both
L6; one is a brecciated white chondrite, L6; one is
a brecciated, veined intermediate chondrite, L5;
and one is a crystalline chondrite, L6. Mabwe-
Khoywa looks like a polymict breccia and has so
far only been classified as "L." All eight meteorites
were analyzed by classical wet chemical techniques
(Jarosewich, 1966). Major phase compositions were
determined by standard electron-probe techniques;
in addition, the abundances of the major phases
(modes) were determined by our previously de-
scribed microprobe technique (Fredriksson, et al.,
1975). Bulk chemical compositions are given in
Table 1; the compositions and abundances of the
major silicates appear in Table 2. The mode and
the norm (mineralogical composition calculated
from the chemical analysis) are presented in
Table 3.
These chondrites are listed, classified and/or
described by Cotter (1912), Hey (1966), Mason
(1975), Silberrad (1932); their olivine compositions
were given by Mason (1963, 1967). Detailed infor-
mation on the morphology and the distribution of
samples is given by Murthy, Srivastava, and Dube
(1969) for the Indian falls (all but Karkh and
Mabwe-Khoywa). In the following descriptions we
do not repeat such information, but give a few
more references as required. Rather, we present our
observations on a number of polished thin sections
(some ultrathin prepared by Mr. G. Moreland of
the Smithsonian Institution) and some additional
microprobe analyses not included in Tables 2 and
3. After the name of each chondrite we give perti-
nent references followed by the composition of
71
TABLE 1.?Chemical composition in weight percent
Constituent
Fe
Ni
Co
FeS
SiO2 .
TiO2 .
A12O3 ......
Cr2
FeO
Fe2
MnO
MgO
CaO
Wa20
K20
P2?5H
20+
H20-
C
Total
Total Fe
Atarra Cranganore Karkh
6.87
1.63
0.06
6.91
38.70
0.12
2.26
0.52
lU.32
?
0.31
25.01
1.60
0.92
0.10
0.23
0.27
0.11
0.02
99.96
22.39
Kutt ippuram
6.1+2
l.Ul
0.06
l.kO
38.75
O.lU
2.11
0.50
15.U5?
0.31
23.62
1.89
1.01+
0.11+
0.12
0.27
0.06
0.0U
99.73
23.10
Mabwe Khoywa
6.1+3
1.23
0.06
6.58
39.U7
0.12
2.U0
0.55
11+.36
?
0.31
21+.1+8
1.83
0.93
0.10
0.21
0.80
0.09
0.19
100.ik
21.77
Mirzapur
6.88
1.1+1
0.07
1+.55
1+0.51
0.11
2.3I+
0.1+6
lU.1+2
?
0.31+
25.26
1.72
1.02
0.10
0.21
0.00
0.11+
0.16
99-70
20.98
Segowlie
1+.16
1.22
0.01+
6.31
39.05
0.16
2.30
0.51
11+.36
3.03
0.33
2U.3I+
1.67
0.96
0.13
0.20
0.35
0.21+
0.06
99.J+2
21.1+5
Sultanpur
6.39
1.20
0.06
5.38
39.90
0.16
2.07
0.51
16.25
?
0.35
21+.21
1.75
0.90
0.10
0.18
0.19
0.11
0.01+
99.75
22.1+U
7.12
1.1+1
0.06
5.37
39.58
0.11+
1.76
0.51+
11+.07
0.31+
21+.87
07ok
12
23
12
0.10
0.61+
100.58
21.1+1+
7.37
1.29
0.06
5.02
39.56
0.11+
2.32
0.51+
11+.06
0.31
21+.68
1.75
1.00
0.11
0.26
1.21
0.17
0.90
100.75
21.1+9
TABLE 2.?Abundance and average composition of major silicate phases
Constituent
Atarra
Olivine
Pyroxene 1
Pyroxene 2
Plagioclase
Cranganore
Olivine
Pyroxene 1
Pyroxene 2
Plagioclase
Karkh
Olivine
Pyroxene 1
Pyroxene 2
Plagioclase
Kuttippuram
Olivine
Pyroxene 1
Pyroxene 2
Plagioclase
Mabwe Khoywa*
Olivine
Pyroxene 1
Pyroxene 2
Plagioclase
Mirzapur
Olivine
Pyroxene 1
Pyroxene 2
Plagioclase
Segowlie
Olivine
Pyroxene 1
Pyroxene 2
Plagioclase
Sultanpur
Olivine
Pyroxene 1
Pyroxene 2
Plagioclase
Mode
Vt.%
33.
18.
8.
1.
37.
19-
6.
9-
33.
26.
-6.
3.
35.
27-
5.
8.
39.
-25
-7
1.
35.
25.
5.
2.
37.
17-
5.
5.
36.
22.
5.
5.
1+
0
8
1
8
8
0
0
9
0
9
0
1+
5
0
1
1+
9
1
0
7
9
6
9
8
3
0
1
6
9
FeO
21.1+
13.7
5.0
-
22.8
Ik
5.3
-
-23
Ik.6
-8.2
-
22.1+
13.6
5
-
-21
-11+
_
-
22.9
13.6
1+.3
-
23.2
1U.3
k.8
-
21+.3
ik.3
5.2
-
CaO
_
0.1
22.1
2.0
_
0.8
20.8
2
_
1.0
-16.1+
2.0
_
0.9
21.1+
2.2
_
-0.7
-
-2
_
1
22.2
1.9
_
0..8
22.3
2.0
_
1.1
22.1+
2.2
MgO
39.6
29.7
17.*+
-
38.8
29
16.9
-
-39
28.8
-20.5
-
39
29.1
16.7
-
~ko
-29
-
-
38.6
28.6
18.1
-
38.8
28.8
17.8
-
36.8
28.3
17.6
-
SiO2
38.6
55.7
51+.2
65.2
38. k
55-7
56.1+
65.2
38.8
56
-55
65.3
38.6
56.6
55
65.O
-39
-56
-
-
38.2
56
5U.9
66
38
55.8
5U.9
65.6
38.9
56.1
5I+.8
65.O
Al,
_
-0
0
21
-0
0
21
-0
~0
21
~0
0
22
-0
0
21
0
0
21
0
0
21
?3
.2
.8
.8
.2
.6
.8
.3
.7
.7
.2
.7
.7
.1
.6
.2
.2
.6
.8
.2
.6
.3
Na
0
10
10
10
0
9
10
10
10
2?
__
.5
.2
-
-
-
.2
-
_
-
.2
_
-
.6
.8
_
_
-
-
-
_
-
.1
-
-
-
.1
_
-
-
.5
K20
_
_
_
1.1
-
-
-
1.1
-
_
-
1.0
-
-
(TiO,
1.0 '
-
_
-
-
-
_
-
0.7
-
-
-
1.0
-
-
-
1.0
MnO
-0.3
-
-
-
-0.2
-
-
-
-0.3
-
-
-
-0.3
, 0.5)
-
-
-
-
-0.3
_
-
-
-0.3
-
-
-
-
-
-
*01ivine and pyroxenes variable, see description.
NUMBER 19 73
TABLE 3.?Normative and modal compositions in weight percent
Phase
Ni/Fe
FeS
Ap
Cr
11
Or
Ab
An
Wo
En
Fs
Fo
Fa
C
Others
Residue
Total
Phase
Ni/Fe
FeS
Ap
Cr
11
Or
Ab
An
Wo
En '
Fs
Fo
Fa
C
Others
Residue
Total
Atarra
Norm
8.59
5.37
0.85
0.26
0.72)
7.96} 8.87
0.19'
1+.01/
17.63> 29.02
7.38)
o'.61+
0.1*8
Mode
10.1
3.8
1.1
8-8U*
18.0/ 26'
33.1*
21*.8
100.0
Mabwe Khoywa
Norm
7.72
6.58
0.50
0.88
0.23
0.6l)
7.86) 10.53
2.06)
2.31+/
l8.38f 26.68
7.96!
29.?5 I j.^, go
11*.17/ J
0.19
Mode
1*.8
3.6
0.3
1.9
31.9
31*. 9
22.6
100.0
Cranganore
Norm
8.72
5.02
0.60
0.85
0.26
0.67
8.1*1+
1.50
2.33
8 18.23
7.67
30.09
13.91+
0.90
I
Norm
8.37
1+. 55
0.50
0.73
0.21
0.6l
8.59
1.50
2.35
18.1*6
7.81
30.93"
ll*.l+7
0.16
/
[ 10.61
'
/
> 28.23
} 1*1*. 03
tfirzapur
10.70
28.62
.1*5.1+0
Mode
1+.5
6*.O
0.2
9.0
19.8/ 25'
37.8
16.7
100.0
Mode
7.5
3.5
0.1*
2.9
5.71
25.0) JU-'
35.1
19.9
99.9
Norm
8.56
6.91
0.5I*
0.83
0.23
0.6l
7.76
1.75
1.93
3 -16.66
7.0l*
Si 83
0.02
Karkh
/
? 10.12
/
? 25.63
^?1*6.60
Segowlie
Norm
5.1*2
6.31
0.1+7
O.83
0.30
0.78'
8.12
1.56'
2.61*/
16.66!
7.26^30.60*
11+.70
0.06
3.36
10.1+6
26.56
f 1*5.30
Mode
6.1
U.i
0.1
3.0
33.9
19.9
100.0
Mode
6.7
6.6
5.3
17;9} 23.7
37.6
(Goethite)
20.1
LOO.O
Kuttippuram
Norm
7.89
7.1+0
0.27
0.81
0.26
0.83!/
8.80]0.61+)
3.32.)
7.03'
30.82\
16.1+3/
0.0U
10.27
21+.90
1+7.25
Mode
5.5
5.9
8.1
ni
27is/ 32'5
35.1+
12.6
100.0
Sultanpur
Norm
7.65
5.38
0.1+1*
O.76
0.30
0.6l
7.60
1.28
2.59/17.96[
8.91'
i6.'iu}
0.01+
9.1+9
29.1+6
U5.6O
Mode
7-1
3.7
0.2
5.9
22.1/ ' '
36.0
19.1
100.0
olivine in mole percent fayalite (Fa), pyroxene in
mole percent wollastonite (Wo), enstatite (En), and
ferrosilite (Fs), plagioclase in mole percent ortho-
clase (Or), albite (Ab), and anorthite (An). These
data are followed by observations on texture,
analyses of phases of special interest or significance,
etc.
ACKNOWLEDGMENTS.?We are grateful to the for-
mer Director General of the Geological Survey of
India, Dr. C. Karunakaran, for encouraging this
study. Mr. R. K. Sundaram and Drs. S. V. P.
Iyengar and M. V. N. Murthy also gave much
assistance. We are indebted to the Smithsonian
Systems Analysis Division for data reductions. The
work has been supported in part by grants from
the Smithsonian Research Foundation (Sg 3352213
and 3352363) and Foreign Currency Program.
Description of Samples
ATARRA
Olivine: Fa248
Pyroxene: Wo2 EnT, Fs^
Plagioclase: Or5 Ab78 An17
The stone has been classified as a black chondrite
and L4. We would rather call it a gray (or inter-
mediate) veined chondrite, while the L4 designa-
tion seems appropriate (Figure 1). The olivine
composition is remarkably constant: 30 randomly
74 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
selected olivines varied between 16.4% and 16.8%
Fe. In the dominant pyroxene (Pyroxene 1, Table
2), the iron varies between 10.0% and 12.4% Fe.
Abundant shock effects are visible: twisted pyroxene
lamellae in radiating pyroxene chondrules, and
fracturing and wavy extinction in olivine crystals.
CRANGANORE
Walker, 1924
Olivine: Fa24.7
Pyroxene: Wo,., Enn Tsa
Plagioclase: Or9 Ab7T An1T
Cranganore has been classified as a gray chond-
rite and L6, which generally agrees with our obser-
vations, although the hand specimen is rather rusty
and more crumbly than most L6 chondrites. Most
thin sections show a structure similar to that in
Figure 7 (Segowlie), but some parts show fairly well-
delineated chondrules, and approach an L5 texture.
The matrix is mostly fragmental to hypidiomorphic-
granular, but the grain size varies considerably
within millimeter or centimeter distances; this
indicates that the last recorded event was breccia-
tion not recrystallization.
FIGURE 1.?Photomicrograph of thin section of the Atarra L4 chondrite. The stone is fragmentary
with relatively few chondrules, while the olivine composition is constant throughout. Length
of section, 4.5 mm.
NUMBER 19 75
KARKH
Fermor, 1907
Olivine: Fa23 a
Pyroxene. Wo02 En^ Fs*,
Plagioclase: Or4 Ab78 An18
This stone has been classified as a gray chondrite
and as L6, which seems appropriate. Our hand spec-
imens, although small, shows some brecciation or
veining; shock effects are also evident in the thin
sections. The clinopyroxene (Pyroxene 2, Table 2)
in Karkh is more inhomogeneous and also has
distinctly lower Ca and higher Fe than the almost
pure diopsides in the other seven chondrites, in-
FIGURE 2.?Photomicrograph of thin section of the Karkh L6
chondrite. Quartz-corundum normative glass, white, between
olivine bars, light gray, in a "ghost" chondrule. Opaques are
nickel-iron and troilite. Length of section, 0.6 mm.
eluding Cranganore, described above, which also is
an L6 gray chondrite. Another anomaly is the
presence of small amounts of silica-alumina-rich
glass found mostly in ghost chondrules, i.e., barely
distinguishable in thin sections (Figure 2), and also
in the matrix as completely integrated fragments of
chondrules. This clear, perfectly isotropic glass is
rather inhomogeneous as exemplified below. All
values are in weight percent.
Analysis SiO2 A12O3 FeO MgO CaO K2O Na2O
2 62 21 2.8 4.8 3.8 1.1 5.6
7 71 23 0.7 0.2 2.7 0.9 1.8
20 77 15 0.6 0.5 0.5 1.0 4.2
23 66 23 0.4 0.2 0.2 0.9 7.1
Analyses 2 and 7 were made in the indistinct
chondrule shown in Figure 2; analyses 20 and 23 in
an integrated chondrule fragment. In all cases the
glass is quartz (^10% to ^50%) and corundum
(<~4% to ^14%) normative and is thus not simply
vitrified plagioclase. Although shock melting may
have occurred, the glass, and probably its parent
material, is not in equilibrium with the major
olivine-pyroxene phases.
KUTTIPPURAM
Keil and Fredriksson, 1964
Olivine: Fa^.g
Pyroxene: Woj., En78 Fs^
Plagioclase: Ors Ab79 An19
This meteorite has been described as a veined
white crystalline hypersthene chondrite and L6,
appropriate for the main part. Our small sample
and also one thin section (Figure .3), however, con-
tain fragments consisting mainly of olivine, acces-
sory pyroxene, and interstitial Si-Al-rich glass, with
practically no metal or troilite. It is remarkable that
olivine is of the same composition in both parts:
22.5 ?0.5% FeO. The glass is fairly constant in
composition with ?67?1% SiO2 21.5?1% A12O3,
2.1% CaO. Sodium and potassium are somewhat
variable (also the Na/K ratio); our best estimate is
^10% Na2O and 0.8% K2O. Thus the glass is
consistently quartz (,?'10%?20%) and corundum
(""6%) normative and resembles the average glass
in the Karkh chondrite described above.
MABWE-KHOYWA
Coulson, 1940
Olivine: Variable, dominant Fa^.^; minor Fa_i0, others pres-
ent
Pyroxene: Variable, dominant Wo,, En_78 Fs^21 (extreme
Wo2 En6, Fsao); minor strongly variable diopsides; enstatite,
rare ?Wo2 Ena0 Fs8
Though it has been classified as an L or hyper-
76 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
FIGURE 3.?Photomicrograph of thin section of the Kuttip-
puram L6 veined white chondrite. Note the "achondritic"
fragment, lower half, consisting mostly of olivine and glass,
and almost devoid of metal and troilite. The olivine-pyroxene
composition in the fragment is the same as in matrix and
chondrules. Length of section, 3 mm.
sthene chondrite, the variable olivine-pyroxene
composition and especially Figures 4 and 5 illus-
trate why the classification is exceedingly difficult.
Our sample of Mabwe-Khoywa is a complex rock, a
breccia or conglomerate. In addition to a great
variety of chondrules it contains lithic fragments,
rounded or angular; some of these were pre-existing
chondrites, while others appear to be achondritic.
Most olivines and pyroxenes, 90%-95% in these
parts, with the exceptions described below, still are
in the dominant range, as are numerous individual
larger mineral fragments. The main part of the
matrix also consists of comminuted chondrules and
chondrite fragments. In general, but not always,
olivines in the matrix seem to be richer in iron than
olivines in fragments, while the lowest iron content
is found in some rare chondrules (Figure 5). Also,
the larger olivines in the "achondritic" fragments
are more iron rich, similar to the dominant olivine,
than the smaller grains. At least three types of
pyroxene were found. The dominant orthopyroxene
is found in almost all types of chondrules and frag-
ments and is essentially homogeneous, i.e., equili-
brated. The diopsidic pyroxene varies at least from
Wo20 to Wo40 with corresponding variations in iron
and magnesium. The third pyroxene, approxi-
mately enstatite, is rare and was only found in
random point analyses (several hundreds) and,we
could not establish in which kind of fragment it
occurs. A few pyroxenes in the range between the
orthopyroxene and the diopside could represent
overlap between host crystals and exsolution
lamellae.
Some of the chondrules and fragments in Figure
4 deserve brief individual descriptions. In the
olivine-pyroxene chondrule (Figure 5), the olivine
has the lowest iron content encountered, and most
crystals are zoned from Fa8 in the center to Fa10 at
the edge. The pyroxene appears to be monoclinic
and has exsolution lamellae, but nearly constant
composition (^Woj En87 Fs12); thus the nonparallel
extinction and the exsolution lamellae are probably
shock produced. Further indication of shock effects
is the opaque spherule consisting of apparently
quenched eutectic troilite plus nickel-iron similar
to those in the H-chondrite Pulsora (Fredriksson,
et al., 1975).
Adjacent to the chondrule is a chondritic frag-
ment containing a fragment of a barred olivine and
glass chondrule. The olivine bars (Figure 5) seem
intergrown with the first chondrule but belong to
the equilibrated main type, Fa^,24. Also other
olivines and pyroxenes in this chondrite fragment
belong to the main type. The glass in the barred
chondrule is almost albitic but has slight normative
excesses of quartz and corundum.
Figure 4 shows a large "achondritic" fragment
consisting largely of olivine and glass with metal,
troilite, and chondrules conspicuously lacking. The
smaller olivine crystals have low iron content,
Fa^,12, while the larger crystals are somewhat zoned
but close in composition (Fa20_22) to the "equili-
brated" main olivine. This might indicate that the
larger crystals are relatively late xenoliths. The
interstitial glass is enriched in silica (^62%) and
alumina (^8%), but has low soda (^0.8%) and
substantial amounts of iron (16% FeO) and mag-
nesia (
NUMBER 19 77
FIGURE 4.?Photomicrograph of thin section of the hypersthene chondrite. Mabwe-Khoywa.
The chondritic main mass is L3 or L4, olivines in most chondrules and fragments have
approximately Fa24; one chondrule indicated by arrow and shown in Figure 5 has Fas.u. In
the achondritic fragment (right), the small olivines are in the range Fa,i.14, some of the larger
Fa2o.23, while the interstitial glass is albitic with excess normative quartz and corundum. Length
of section, 12.5 mm.
The olivine with highest iron content was found
in a lithic fragment (possibly a chondrule). The
crystal has 25.5% FeO (Fa28) in the center and 24%
at the edge. Adjacent glass is again mostly albitic
but has a substantial excess of normative corundum
along with some iron and magnesium. It is remark-
able that Mabwe-Khoywa in spite of all this
diversity of components has a bulk composition
almost identical to the other L-chondrites. Indeed,
even the abundances and average compositions of
the phases are close. Mabwe-Khoywa is apparently
the product of multiple impacts, and after the first,
or first few, impacts its chemistry was not sig-
nificantly altered.
MIRZAPUR
Olivine: Fs24.s
Pyroxene: Wo
Plagioclase: O
En78 Fs2i
4 Ab^ AnJ7
It has been classified as a veined intermediate
chondrite (Cia) and L6; we prefer L5 (towards L4)
because our specimen is relatively unconsolidated
and the thin sections show well-delineated chon-
78 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
FIGURE 5.?An Mg-rich olivine and pyroxene chondrule
(shown by arrow in Figure 4), is lined with nickel-iron and
troilite, black. It is intergrown with matrix (lower right) and
with a fragment of a barred "equilibrated" olivine (Fa^)
chondrule (lower left), which is part of a fragment of pre-
existing chondrite (shown under arrow in Figure 4). Length
of section, 0.6 mm.
drules (Figure 6), some with Si-Al enriched and only
partly devitrified glass. This glass has approxi-
mately 66% SiO2, 21% A12O3, and 8% soda; the
normative composition is again almost albitic with
some quartz and minor corundum and pyroxene.
Shock alterations, including fracturing wavy extinc-
tion and veining (Fredriksson, et al., 1964), are
abundant and the glass may be impact-produced;
however, it would hardly be in equilibrium with
olivine-pyroxene at metamorphic temperatures of
800? to 1000? C.
SEGOWLIE
Olivine: Fa^.o
Pyroxene: Woj s En77 Fs^
Plagioclase: Or5 Ab7S AnJ7
Segowlie perfectly fits the definitions for a crys-
talline chondrite and almost as well for the L6
group. The photomicrograph in Figure 7 shows
individual patches with equigranular, recrystallized
structure, identical to that in the H-chondrite
Andura (Fredriksson, et al., 1975). However, the
grain size varies grossly between the different parts,
i.e., the stone is still a breccia. Thus it seems
unlikely even in this case that the structure is due
to simple metamorphic recrystallization. Some parts
(Figure 8) also show rather well-delineated chon-
drules, i.e., a structure more like L5.
SULTANPUR
Walker, 1924; Coulson, 1940
Olivine: Fa^.,
Pyroxene: Wo, En78 Fs22; W044
Plagioclase: Or5 Ab77 An18
Sultanpur has been classified as a black chondrite
and an L6, but both designations are somewhat
questionable. It is more a black chondrite than
Atarra, but not in the same sense as shock products
like Farmington and McKinney (Fredriksson, et al.,
1964; Heymann, 1967). Sultanpur seems rather to
be close to a brecciated (and veined) gray chon-
drite. The grain size is much finer and the
chondrules better defined than in the L6 Segowlie;
thus Sultanpur could probably also be an L5,
particularly because the plagioclase does not occur
as clear, well-defined grains. Evidence of shock
effects, e.g., fracturing and undulatory extinction,
in both olivine and pyroxene are common,
however.
Discussion
Bulk and phase compositions, as well as phase
abundances (Tables 1, 2), clearly show the close
relation among these eight meteorites in spite of
their different appearances and classifications. Essen-
tially only the contents of nickel-iron and troilite
vary significantly (Table 3), while the silicate frac-
tions are chemically almost identical even in the
obviously fragmentary Mabwe-Khoywa. The sili-
cate fraction compositions in Table 4 were obtained
by deducting metal, troilite, Fe for ilmenite and
chromite, and Ca for apatite from the bulk analysis.
While normative and modal amounts of pyroxene
are close, both olivine and plagioclase are higher
in the norm, which must be compensated for by
NUMBER 19 79
.?#
FIGURE 6.?Photomicrograph of thin section of the Mirzapur, L5 veined intermediate chondrite
(see text). Note the black, opaque, shock veins and shock altered areas in the center. The
chondrules are quite distinct, although often deformed in some parts. Length of section,
?20 mm.
the modal residue. Because the residue in the
modal analyses (Table 3) is substantial, an attempt
has been made to establish its chemical composition
by deducting the components of the modal min-
erals and normative metal, sulfide, chromite,
ilmenite, and apatite from the bulk analyses. The
compositions of these residues are compared to the
bulk silicates in Table 4. Although this modal
residue is largely due to overlap between grains
in the probe analysis, it appears that in all cases
except for Atarra, the residue has 1-3% normative
corundum (A12O3) and more iron-rich, including
Atarra, normative olivine than the bulk silicates.
Thus all these L-chondrites appear to have small
amounts of a matrix component enriched in Al
and Fe, similar to the H-chondrites previously
described by Fredriksson, et al. (1975). Moreover,
the comparison in Table 5 of the bulk silicate
80 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
FIGURE 7.?Photomicrograph of thin section of "normal" part of the Segowlie, L6 crystalline
chondrite. Note the extreme integration of the chondrule (right), which is, however, fine-
grained (as is part of the matrix above it) compared to the adjacent matrix. Length of section,
4.5 mm.
compositions of our eight L-chondrites with the
four H-chondrites described by Fredriksson, et al.
(1975, table 4) shows that they differ essentially
only in the FeO content; if normalized to the same
FeO content, the silicates seem identical within
analytical uncertainties.
Conclusion
Eight L-chondrites with different textures and
classifications are chemically and mineralogically
almost identical. This indicates a similar origin
from chemically the same parent material and by
the same processes, probably impact events.
The silicate compositions in these L-chondrites,
except for the FeO contents, are close to those of
four previously described H-chondrites (Fredriksson,
et al., 1975), and if normalized to the same iron
content, the silicates are chemically identical. Thus,
we imply a common parent material for H- and L-
(also LL-) chondrites. The essential difference
between the groups only lies in the amounts of iron
reduced and the portion of such produced metal
remaining. Chemically the parent material might
well have been close to the main semi-amorphous
silicates in the carbonaceous chondrites such as
Ivuna or Orgueil (Bostrom and Fredriksson, 1966).
Early impacts may have caused the chemical altera-
TABLE 4.?Chemical composition of bulk silicates from chemical analyses and of unidentified
fractions "residue" in the modal analyses
Constituent
SiOp
A12O3
FeO+MnO
MgO
CaO*
KaoO
KoO
Constituent
SiO2 .
A12O3
FeO+MnO
Ma-0
CaO* ....
Na20
KoO
Atarra
Silicate
fraction
83%
of total
1*7.5
2.1
16.8
29.8
2.1+
1.2
0.1
Mabwe
Silicate
fraction
82. k%
of total
1+7-3
2.917.2
29. k
2.0
1.1
0.1
Residue
2U.85S
of total
50.36.U
17. h
21.U
0.0
1+.0
0.5
Khojrwa**
Cranganore
Silicate
fraction
83$
of total
1+7.5
2.8
16.7
29.9
2.1
1.2
0.1
Residue
16.7$
of total
kk.9
2.6
20.7
30.7,
0.0
0.9
0.1
Mirzapur
Silicate
fraction
85%
of total
1+7-5
2.7
16.9
29.3
1-9
1.2
0.1
Residue
19-9/5
of total
U8.2
10.0
15.8
21.1
0.0
h.k
0.5
Karkh
Silicate
fraction
82. k%
of total
1+6.8
2.7
17.1
30.2
1.8
1.1
0.1
Residue
19-9$
of total
1+2.2
12.516.0
23.6
0.0
5.1
0.6
Segowlie
Silicate
fraction
82$
of total
i+7.3
2.8
17.3
29.5
1.9
1.2
0.2
Residue
20.1J?
of total
51.1
6.716.6
22.1+
0.0
2.6
0.5
Kuttippuram
Silicate
fraction
82$
of total
1+6.8
2.5
18.5
28.5
2.2
1.3
0.2
Residue
12.6JS
of total
22.6
2.6
51.3
11+.6
fc.7
3.3
0.9
Sultanpur
Silicate
fraction
81+. 5%
of total
1+6.9
2.1+
19.1
28.5
1.9
1.1
0.1
Residue
19.1$
of total
1+3.8
M2k.k
21+.7
0.0
1.9
0.3
*The zero value for calcium in the "residue" is artificial (calculated) because of uncertainties in the amount and
composition of Pyroxene 2, Table 2.
**Residue not determined (see text).
^&S^
*v -v ;?? . W:S
TABLE 4.?Silicate composition of eight L- and four H-group
chondrites
Constituent
AI2O3
FeO
MgO
CaO
Na2O
K2O
8 L-Group
Min. Average Max.
4 H-Group*
Min. Average Max.
46.8
2.1
16.7
28.5
1.8
1.1
0.1
47.2
2.6
17.5
29.4
2.0
1.2
0.1
47.5
2.9
19.1
30.2
2.4
1.3
0.2
47.8
2.4
12.7
30.4
2.2
1.1
0.1
48.7
2.9
13.7
31.0
2.5
1.2
0.1
49.2
3.2
15.4
31.5
2.7
1.2
0.2
*Data fran Fredriksson, et al., 1975
tions, e.g., loss of volatiles, and extensive melting
and drop (chondrule) formation because of low
density and high compressibility of the target ma-
terial. Later impacts on a parent body caused more
brecciation, destruction of preexisting chondrules
and chondrites, and "solid state" recrystallization
rather than melting and formation of liquid drop-
lets, i.e., new chondrules, although this must also
have occurred as it did on the moon.
FIGURE 8.?Photomicrograph of thin section of chondritic part
of the Segowlie chondrite (cf., Figure 7). Note the patchy
variation in grain size. Length of section, 3.6 mm.
82 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
Literature Cited
Bostrom, K., and K. Fredriksson
1966. Surface Conditions of the Orgueil Meteorite Parent
Body as Indicated by Mineral Associations. Smith-
sonian Miscellaneous Collections, 151(3): 1-39.
Cotter, G. de P.
1912. Notes on Indian Aerolites Recorded since 1906.
Records of the Geological Survey of India, 42:265-
277.
Coulson, A. L.
1940. Catalogue of Indian Meteorites. Memoirs, Geologi-
cal Survey of India, 75:1-346.
Femor, L. L.
1907. Notes on Some Indian Aerolites. Records of the
Geological Survey of India, 35:90-02.
Fredriksson, K., P. DeCarli, R. O. Pepin, J. H. Reynolds, and
G. Turner
1964. Shock Emplaced Argon in a Stony Meteorite. Jour-
nal of Geophysical Research, 69:1403-1411.
Fredriksson, K., A. Dube, E. Jarosewich, J. Nelen, and A.
Noonan
1975. The Pulsora Anomaly: A Case against Metamorphic
Equilibration in Chondrites. In George S. Switzer,
editor, Mineral Sciences Investigations 1972-1973.
Smithsonian Contributions to the Earth Sciences,
14:41-53.
Hey, M. H.
1966. Catalogue of Meteorites. 3rd edition, 637 pages.
London: British Museum of Natural History.
Heymann, D.
1967. On the Origin of Hypersthene Chondrites: Ages and
Shock Effects of Black Chondrites. Icarus, 6:189-
221.
Hobson, G. V.
1927. Six Recent Indian Aerolites. Records of the Geo-
logical Survey of India, 60:128-152.
Jarosewich, E.
1966. Chemical Analyses of Ten Stony Meteorites. Geo-
chimica et Cosmochimica Acta, 30:1261-1265.
Keil, K., and K. Fredriksson
1964. The Iron, Magnesium, and Calcium Distribution in
Coexisting Olivines and Rhombic Pyroxenes of
Chondrites. Journal of Geophysical Research,
69:3487-3515.
Mason, B.
1963. Olivine Composition in Chondrites. Geochimica et
Cosmochimica Acta, 27:1011-1023.
1967. Olivine Composition in Chondrites?A Supplement.
Geochimica et Cosmochimica Acta, 31:1100-1103.
1975. List of Meteorites in the National Museum of Nat-
ural History, Smithsonian Institution. In George S.
Switzer, editor, Mineral Sciences Investigations 1972-
1973. Smithsonian Contributions to the Earth
Sciences, 14:71-83.
Murthy, M. V. N., S. N. P. Srivastava, and A. Dube
1969. Indian Meteorites. Memoirs, Geological Survey of
India, 99:1-192.
Silberrad, C. A.
1932. List of Indian Meteorites. Mineralogical Magazine,
23:290-304.
Walker, H.
1924. Recent Falls of Aerolites in India. Records of the
Geological Survey of India, 55:133-142.
Wasson, J. T.
1974. Meteorites. 316 pages. New York: Springer-Verlag.
The Ras Tanura, Saudi Arabia, Chondrite
Brian Mason
ABSTRACT
The Ras Tanura meteorite, which fell near
Dhahran, Saudi Arabia, on 23 February 1961, is an
olivine-bronzite (H6) chondrite; principal minerals
are olivine and orthopyroxene, with minor amounts
of plagioclase, nickel-iron, and troilite, and acces-
sory chromite and whitlockite.
The Ras Tanura meteorite was an observed fall
on 23 February 1961 at approximately 1142 GCT.
An eyewitness at Dhahran, about 40 km south of
the point of fall (26?40'N, 50?09'E) described the
event as follows:
A distinct boom similar to a sonic boom was heard, fol-
lowed by a rolling rumble, like thunder. In an otherwise
perfectly clear sky there appeared a dense white cloud with a
less dense zig-zag tail trailing away to the south. The tail
indicated a track from south to north. The tail disappeared
after about 10 minutes. The dense white cloud persisted for
about 30 minutes. During this time it drifted slowly to the
east about 15?. The cloud diameter subtended an angle of
about 2?. The elevation angle was about 60?. The object
was observed on an azimuth of approximately 10?.
A single small crusted stone, weight approxi-
mately 6 grams, is all that was recovered. It was
picked up on the South Pier of the Aramco refinery
at Ras Tanura. One observer believed he saw a
waterspout offshore as if caused by a falling body
"shortly after the explosion." It is thus probable
that the main mass of the meteorite fell in the sea.
Brian Mason, Department of Mineral Sciences, National Mu-
seum of Natural History, Smithsonian Institution, Washing-
ton, D. C. 20560.
The stone was turned in to Aramco officials, who
forwarded it to the Air Force Intelligence Center,
Wright-Patterson Air Force Base, Ohio, as an
unidentified flying object. It was eventually trans-
ferred to the Smithsonian Astrophysical Observa-
tory and thence to the National Meteorite Collec-
tion, where it is cataloged as USNM 2171.
Ras Tanura is a well-recrystallized olivine-
bronzite chondrite, H6 in the Van Schmus-Wood
classification. A cut surface shows abundant metal
particles in a pale gray matrix; no chondrules are
visible. A slight amount of rusting has taken place
in association with the metal particles. In thin
section the meteorite shows an allotriomorphic-
granular texture. Average grain size is approxi-
mately 0.1 mm, but with scattered larger olivine
grains, up to 0.5 mm. Sparse chondrules are recog-
nizable by textural differences, principally a coarser
grain size and interstitial fine-grained material
(probably devitrified glass), and by a vaguely circu-
lar outline.
The principal minerals are olivine and ortho-
pyroxene. Microprobe analyses give a composition
of Fa^.o for the olivine and Fs174 for the ortho-
pyroxene; the orthopyroxene contains 0.75% CaO.
A small amount of diopside, composition Wo44En50-
Fs6, is associated with the orthopyroxene; the
diopside contains 0.53% Na2O, 0.31% TiO2, and
0.73% Cr2O3, whereas the orthopyroxene contains
<0.1% Na2O, 0.10% TiO2, and 0.14% Cr2O3.
Plagioclase, composition An10 with a K2O content
of 0.95%, is also present. Accessory whitlockite
was identified with the microprobe. The opaque
minerals are nickel-iron, troilite, and chromite.
83
Geochemical Differences among
Components of the Allende Meteorite
Brian Mason and Philip M. Martin
ABSTRACT
Four discrete groups of inclusions have been distin-
guished in the Allende meteorite. Group I are
melilite-rich chondrules; Groups II and III are ag-
gregates made up largely of spinel and fassaite;
Group IV are olivine-rich chondrules and aggre-
gates. Groups I, II, and III have been previously
classed together as Ca/Al-rich inclusions, but each
group has a distinctive trace-element pattern, most
clearly shown by the lanthanide distribution. Group
I has a relatively unfractionated pattern (with a
small positive Eu anomaly) at about 10?15 times
chondrites; Group II a highly fractionated pattern
with depletion of the heavier lanthanides and neg-
ative Eu and positive Tm and Yb anomalies; Group
III an unfractionated pattern at about 20 times
chondrites, except for negative Eu and Yb anom-
alies; Group IV a relatively unfractionated pat-
tern at 2-4 times chondrites. The Yb anomalies can
be ascribed to highly reducing conditions produc-
ing Yb 2+, or to fractional condensation in a cool-
ing nebula; the Tm anomaly may be due to frac-
tional condensation or some unrecognized factor.
The complex pattern of trace element distribution
in these Allende inclusions indicates a complex
history of formation of this meteorite from the an-
cestral nebula.
Introduction
The fall of the Allende meteorite on 8 February
1969, provided a large amount of a Type III car-
bonaceous chondrite for research. A detailed de-
scription of the fall and recovery, and of the
Brian Mason, Department of Mineral Sciences, National Mu-
seum of Natural History, Smithsonian Institution, Washing-
ton, D. C. 20560. Philip M. Martin, Geology Department,
University of Leicester, Leicester LEI 7RH, England.
chemical and mineralogical composition of the
meteorite has been published by Clarke, et al.
(1971). The following principal components were
distinguished and their volume percentages esti-
mated by point-counting: matrix, largely of Fe-rich
olivine (^60%), Mg-rich chondrules (<-30%), Ca/
Al-rich chondrules (^5%), and Ca/Al-rich aggre-
gates (^5%). The chondrules and aggregates have
been the subject of intensive research and specula-
tion as to their origin (Marvin, Wood, and Dickey,
1970; Grossman, 1972; Osborn, et al., 1974; Wanke,
et al., 1974). The purpose of this paper is to show
that they comprise at least four groups of distinc-
tive chemical and mineralogical composition. The
differences between the groups are indicative of
extensive chemical fractionations prior to the ac-
cumulation of the components into the parent body
of the Allende meteorite.
ACKNOWLEDGMENTS.?We would like to express
our appreciation to Mr. E. Jarosewich, Mr. J.
Nelen, Dr. A. L. Graham, Mrs. P. Muir, and Mr.
W. Nance for assistance in the analytical work. The
spark source mass spectrometric analyses were made
in the Research School of Earth Sciences, Austra-
lian National University, and we are indebted to
Dr. S. R. Taylor for the use of these facilities over
several weeks in 1971 and 1973. The Smithsonian
Research Foundation and the National Aeronau-
tics and Space Administration (Grant NGR-09-
015-170) contributed part of the costs of this re-
search, and their contribution is gratefully recorded.
Experimental Methods
A large number of Allende specimens in the col-
lection of the National Museum of Natural History
84
NUMBER 19 85
(NMNH) were inspected, and those showing promi-
nent and readily extractable chondrules and ag-
gregates were selected for detailed examination.
From these, over 20 chondrules and aggregates
were extracted and subjected to complete chemical
and mineralogical analysis, and many others investi-
gated to a lesser degree.
As far as possible the chondrules and aggregates
were extracted from the matrix by simple mechani-
cal tools and hand-picking, to avoid introducing
contaminants; however, in some instances methy-
lene iodide was used to separate the denser matrix
from the less dense chondrules and aggregates.
Mineral identification and analysis were carried out
using microscope, x-ray diffraction, and electron-
microprobe techniques. Compositional data for ma-
jor elements and some minor elements were ob-
tained by microprobe analyses of glasses prepared
by fusion with a lithium tetraborate flux. Some of
the analyses of Groups II, III, and IV components
have low summations (90-95%) because of the non-
determination of some elements (Ni, Cr, S) and
possible loss of alkalies during fusion. The trace
element data were obtained by spark source mass
spectrometry, using the procedures described by
Taylor (1965, 1971). The precision is about ?5%
and the accuracy about ? 10%, but they vary some-
what, being poorer for elements below mass num-
ber 105 than for those of higher mass number.
Some trace elements could not be determined be-
cause their concentrations were below the sensitiv-
ity of the technique. Among the lanthanictes, Lu
was not determined because of its use as an internal
standard. The single mass number (169) for Tm
is subject to interference from a multiple carbon
ion, and this element cannot be accurately deter-
mined at low concentrations (<0.3 ppm). The 169
line, however, was unexpectedly strong in Group II
samples, indicating the presence of a positive Tm
anomaly. The platinum metals were observed in
most Groups I and II samples, but accurate deter-
mination was not possible because of the lack of
suitable standards.
Results
The results of the chemical analyses are sum-
marized in Tables 1 and 2 and Figures 1-3.
The Allende samples can be grouped in various
ways using chemical, petrological, and textural
parameters. From such considerations four distinct
groups can be distinguished: Group I: Ca/Al-rich
chondrules with relatively unfractionated lantha-
nide abundance patterns; Group II: Ca/Al-rich ag-
gregates with strongly fractionated lanthanide
abundance patterns: Group III: Ca/Al-rich aggre-
gates with relatively unfractionated lanthanide
abundance patterns, except for Eu and Yb anom-
alies; and Group IV: Mg-rich chondrules and
aggregates, with low and relatively unfractionated
lanthanide patterns.
Group I, the largest group studied, can be char-
acterized as melilite chondrules, rounded bodies up
to 25 mm diameter with melilite (40%-75%), Al/
Ti-rich pyroxene (10%-25%), spinel (10%-25%),
and anorthite (5%?15%) as major phases. Samples
falling in this group are 26, 29, 30, 31, 32, 33,
3529G, 3658, and 3898. They have a coarsely
crystalline igneous texture and are characterized
chemically by high A12O3 (22%-23%), high CaO
(23%-33%), low SiO2 (25%-35%), and a relatively
unfractionated lanthanide abundance pattern aver-
aging 10-15 times chondrites but with a small posi-
tive Eu anomaly.
Sample 5171 probably belongs to Group I but
has a fine-grained texture. It has low A12O3 and
Ba and high Rb compared to other Group I sam-
ples. Mineralogically it is characterized by the
presence of grossular (about 10%), as well as the
major phases melilite, pyroxene, spinel, and anor-
thite.
Another well-defined group, Group II, comprises
samples 37, 3598, 3803, 4691, and 4692, which are
fine-grained irregular aggregates (except for 4691,
which is texturally similar to the chondrules of
Group I), with spinel, pyroxene, melilite and/or
grossular as important phases, and minor contents
of nepheline and sodalite. Their chondrite-normal-
ized lanthanide abundance patterns are very in-
teresting (Figure 1). The light lanthanides (La-Sm)
are relatively high, with rapidly diminishing abun-
dances of the the heavier lanthanides. Superimposed
upon these patterns are marked negative Eu and
positive Tm and Yb anomalies.
The two remaining fine-grained Ca/Al-rich ag-
gregates, 3593 and 4698, classified as Group III,
86 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 1.?Chemical abundances in components of the Allende meteorite (oxides in weight
numbers are individual chondrules and inclusions from NMNH 3529; the figures for the
possess chondrite-normalized Ianthanide abundance
patterns quite distinct from those of Group II.
They have a relatively unfractionated Ianthanide
pattern at about 20 times chondrite abundances,
on which are superimposed marked negative Eu and
Yb anomalies. Group III also have lower average
SiO2 and higher A12O3, Y, Zr, Mo, and possibly Nb
than Group II. Mineralogically, Group III aggre-
gates are characterized by the presence of spinel,
pyroxene, grossular, sodalite, and nepheline; a high
spinel content and the absence of melilite distin-
guish Group III from Group II.
The three samples classified as Group IV, 24,
3529P, and 4060, are characterized by high SiO2
and MgO and low TiO2 contents, and consist
largely of olivine with lesser amounts of clinoen-
statite and glass. They have a relatively low and
unfractionated Ianthanide distribution at 2-4 times
NUMBER 19 87
percent, elements in ppm; 4-digit sample numbers are NMNH catalog numbers, 2-digit sample
bulk composition are from a compilation by Mason, in press)
3598
27.8
0.91*
38.5
1+.5
11.6
13.1+
3.6
0.01+
1.9
21+
0.96
2.3
2.2
?
0.21+
0.18
13
6.7
16
2.6
12
3.3
0.18
1.6
0.20
1.0
0.08
0.22
0.81+
<0.3
0.32
??
Group II
3803
31+.5
0.1+6
19.3
12.2
16.6
8.6
3.1+
0.26
6.1
26
0.86
1.9
0.9I+
0.62
0.1+0
0.12
15
3.7
13
1.6
6.2
2.2
0.17
0.81t
0.12
0.66
0.07
0.15
0.33
0.73
<0.3
0.11+
<0.05
1+691
17.7
1.1
1+1+.0
1.3
10.1
21+.0
0.39
0.02
0.1+2
73
2.6
7.2
2.6
<0.5
0.08
<0.05
22
13
31
k.l
20
6.2
0.62
3.8
0.52
2.6
0.21
0.1+3
0.95
1.6
<0.3
0.72
0.08
I+692
31.6
0.39
30.5
6.8
11.2
11.2
k.l
0.26
5.3
18
0.9!+
2.2
1.2
<0.5
0.35
<0.05
6.2
11
26
k.3
18
5.6
0,13
2.9
0.35
1.6
0.10
0.23
0.72
0.37
<0.3
O.67
Group
3593
21+.5
0.96
1+0.3
3.9
13.6
11.1+
1.8
0.05
1.1
1+3
1+1
113
9-1
9-9
0.20
<0.05
10
5.8
15
2.1
9-9
3.1
O.36
1+.6
0.81
6.5
1.7
k.9
O.Ik
1.9
2.5
0.72
0.09
III
1+698
20.5
0.71+
U3.3
3.7
15.1+
11.1+
1.3
0.01+
1.2
28
36
99
1.9
1+.2
0.19
0.08
21
6.5
11
2.2
11
3.1
0.25
1+.5
0.82
6.5
2.3
6.0
0.77
0.71+
2.2
0.70
2k
1+1+.2
0.18
3.6
11.0
35. k
2.9
0.68
0.03
1.1
20
1+.3
9.9
0.89
?
?
?
11
0.79
1+.8
0.35
1.6
0.1+9
0.13
0.1+6
0.08
0.53
0.13
0.38
?
0.61+
?
?
Group IV
3529P
39.9
0.21+
9.k
10.9
23.5
8.3
2.7
0.20
20
19
1.6
3.8
O.5I+
O.96
7.7
0.62
9.8
1.9
1+.8
0.72
3.1
1.1
0.17
1.1
0.17
0.92
0.15
0.1+2
<0.3
0.1+7
<0.3
0.17
<0.05
1+060
38.8
0.30
6.2
10.5
31.8
5.1
1.6
0.12
1+.3
13
1+.2
11
0.85
1.1
0.18
0.17
9.8
0.99
2.5
0.32
1.7
0.60
0.19
0.70
0.12
0.79
0.19
0.60
<0.3
0.70
0.33
0.06
<0.05
36
35-5
1.98
10.0
16.0
H+.3
18.8
2.11
0.33
5.1+
5.1
16
1+7
3.1
1+.2
0.31
0.32
3.1+
3.2
8.9
1.3
5-9
2.0
O.9I+
2.6
0.1+8
3.3
0.86
2.7
O.36
2.8
1.6
0.33
<0.05
3509
1+0.2
0.12
17.8
8.8
15.2
5.3
10.6
0.6
9.5
26
2.5
25
0.26
l.k
0.1+7
0.23
15
O.56
1.1
0.13
0.50
0.15
0.16
0.18
0.01+
0.27
0.06
0.16
0.1+1
0.29
0.81+
0.22
0.06
361+3
21+.9
1.3
36.3
6.0
7.5
19.9
1.1
0.05
0.1+7
83
7.6
ll+
1+.7
0.60
0.13
0.07
19
1+.1+
ll+
1.8
7.8
2.8
O.69
1.9
0.30
1.8
0.31+
0.91
0.57
2.0
0.38
0.32
0.09
BULK
31+.3
0.15
3.29
27.2
21+.6
2.59
0.1+6
0.03
1.3
11+
3.1
5.8
0.7
2
0.68
0.08
1+.1+
0.1+1+
1.25
0.20
0.91
0.29
0.11
0.1+3
0.07
0.1+2
0.12
0.31
0.05
0.32
0.19
0.062
0.015
chondrite abundances. Texturally 3529P and 4060
are fine-grained aggregates whereas 24 is a large
chondrule with a coarsely crystalline igneous tex-
ture.
Among the samples examined are a few that can-
not be readily accommodated in the fourfold group-
ing here proposed. One such chondrule (3509 in
Table 1) is that described by Clarke, et al. (1971:
39-41, type c chondrule), consisting of nepheline,
sodalite, pyroxene, and olivine; the lanthanide con-
centrations are low (at about average chondritlc
abundances) with a positive Eu anomaly. One fine-
grained aggregate (NMNH 3529-36) has trace ele-
ment abundances similar to those for Group I
chondrules, except for extremely low Sr (5.1 ppm)
and Ba (3.4 ppm) and high Rb (5.4 ppm) and Cs
(0.32 ppm); mineralogically it is notable for a con-
siderable content of grossular. Another fine-grained
88 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 2.?Range and average chemical composition for each of the Allende groups (oxides
in weight percent, elements in ppm; the numbers in parentheses after the group are the
number of specimens analyzed)
Constituent
SiO2
TiO2
A12?3
FeO
MgO
CaO .......
Na2O
K20
Rb
Sr
Y
Zr
Nb
Mo
Ba
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb ,
Dy .
Ho
Er
Tm
Yb ,
Hf
Th
Group I (10)
Range Average
Group II (5)
Range Average
Group III (2)
Range Average
Group IV (3)
Range Average
24.9-35.1
1.0-1.5
21.5-32.6
0.4-3.1
6.9-12.6
23.2-33.3
0.11-0.92
<0.01-0.08
0.05
104
15
35
1.9
7.4
2.3
3.2
8.2
1.2
5.4
1.7
0.76
2.2
0.41
2.5
0.59
1.9
0.30
2.1
-0.97
-197
-29
72
5.1
14.0
104
4.7
12
1.9
9.0
3.2
1.3
4.0
0.71
4.8
1.2
3.8
0.46
3.4
0.83-1.8
0.34-0.61
30.0
1.2
28.6
1.7
9.9
27.7
0.38
0.02
0.33
136
23
56
3.7
11
57
4.1
10.5
1.6
6.8
2.2
1.0
3.1
0.53
3.7
0.94
2.8
0.38
2.6
1.3
0.45
17.7-34.5
0.30-1.1
19.3-44.0
1.3-12.2
10.1-16.6
8.6-24.0
0.39-4.7
0.02-0.26
0.42-6.1
18-73
0.86-3.0
1.9-7.2
0.94-2.6
<0.7
6.2-19
3.7-13
10-31
1.6-4.7
6.2-20
2.2-6.2
0.13-0.62
0.84-3.8
0.12-0.52
0.66-2.6
0.07-0.22
0.15-0.43
0.33-0.95
0.37-1.6
<0.3
0.14-0.72
28.9
0.64
30.3
7.1
12.8
13.2
3.1
0.12
3.2
37
1.7
4.1
1.7
<0.7
15
7.8
19
3.0
13
4.0
0.28
2.3
0.31
1.6
0.14
0.26
0.67
0.81
<0.3
0.46
20.5-24.5
0.74-0.96
40.3-43.3
3.7-3.9
13.6-15.4
11.4
1.3-1.8
0.04-0.05
1.1-1.2
28-43
36-41
99-113
1.9-9.1
4.2-9.9
10-21
5.8-6.5
11-15
2.1-2.2
9.9-11
3.1
0.25-0.36
4.5-4.6
0.81-0.82
6.5
1.7-2.3
4.9-6.0
0.74-0.77
0.74-1.9
2.2-2.5
0.70-0.72
22.5
0.85
41.8
3.8
14.5
11.4
1.6
0.05
1.2
35
39
106
5.5
7.0
16
6.2
13
2.2
10.5
3.1
0.31
4.6
0.82
6.5
2.0
5.5
0.76
1.3
2.4
0.71
38.8-44.2
0.18-0.30
3.6-9.4
10.5-11.0
23.5-35.4
2.9-8.3
0.68-2.7
0.03-0.20
1.1-20
13-20
1.6-4.3
3.8-11
0.54-0.89
0.96-1.1
9.8-11
0.79-1.9
2.5-4.8
0.32-0.72
1.6-3.1
0.49-1.1
0.13-0.19
0.46-1.1
0.08-0.17
0.53-0.92
0.13-0.19
0.38-0.60
<0.3
0.47-0.90
<0.3-0.33
0.06-0.17
41.0
0.24
6.4
10.8
30.2
5.4
1.7
0.12
8.5
17
3.4
8.2
0.76
1.0
10
1.2
4.0
0.46
2.1
0.73
0.16
0.75
0.12
0.75
0.16
0.47
<0.3
0.60
0.3
0.12
aggregate (NMNH 3643), also with a considerable
grossular content, has trace element concentrations
generally similar to those of Group II, but its lan-
thanide distribution pattern lacks the characteristic
negative europium anomaly. Further search will
probably turn up additional unique chondrules
and aggregates in the Allende meteorite.
The Ca/Al relationship between the four groups
deserves special attention, since it has been shown
that this ratio (by weight) is practically constant at
1.09 in chondrites (Ahrens and von Michaelis,
1969). Figure 2 shows that Groups I, II, and III ma-
terials deviate widely from this ratio, whereas
Group IV materials are close to it. The figure also
illustrates a significant compositional difference be-
tween Group I and Groups II and III, Group I
NUMBER 19 89
having a relatively high Ca/Al ratio, the latter two,
relatively low ones. Mineralogically this is ex-
pressed by the dominance of melilite in Group I
samples, and its absence or presence in only minor
amounts in other samples (except 4691).
Some other features of major element chemistry
deserve notice (Table 2). Group IV is consistently
higher in SiO2 and MgO and lower in TiO2 than
the other groups. In Group I, Na2O and FeO are
notably low; in fact, some of these melilite chon-
drules are essentially iron- and alkali-free, and the
ferrous iron and alkali in others may have been a
later introduction, since microprobe analysis shows
that these elements are concentrated at the chon-
drule margins.
Returning now to the trace element data, we
find characteristic differences between the different
groups. Group I samples have notably high Sr and
low Rb, giving unusually high Sr/Rb ratios. Gray,
Papanastassiou, and Wasserburg (1973) and Weth-
erill, Mark, and Lee-Hu (1973) have analyzed sim-
ilar samples with concordant results, and they have
also found that the 87Sr/86Sr ratios are the lowest
yet recorded, i.e., the Sr is "primordial" and has
had essentially no radiogenic 87Sr added to it. Other
Allende samples analyzed by them have much
higher Rb, lower Sr, and higher 87Sr/86Sr ratios, and
probably belong to Group II or Group III as these
are denned here.
The neighboring elements Y, Zr, and Nb show
rather coherent geochemical behavior, with a dis-
tinctive pattern in each of the four groups. They
are most highly enriched in Group III (however,
only two samples were analyzed, so the statistical
basis is weak), notably enriched (at about 10 times
chondritic level) in Group I, and relatively low (at
about average chondritic level) in Groups II and
IV. On examining the data for the individual
samples (Table 1), an interesting relationship is ap-
parent; the ratio Zr/Nb varies considerably from
1.1 to 53, whereas the ratio Zr/Y is remarkably con-
stant, ranging only from 2.1 to 2.9. The Zr/Y co-
Yb
FIGURE 1.?Chondrite-normalized lanthanide abundance patterns of the average of each group
and of a bulk sample of the Allende meteorite: Group i: Ca, Al-rich chondrules; Groups n and
m: Ca, Al-rich aggregates; Group iv: Mg-rich chondrules and aggregates. Note the Eu and Yb
anomalies in Groups n and m and the Tm anomaly in Group n.
90 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
herence is illustrated in Figure 3. The wide range
of Zr/Nb ratios is somewhat surprising, since
Graham and Mason (1972) found a limited range
(10-32) for this ratio over a variety of meteoritic,
lunar, and terrestrial materials. A geochemical co-
herence between Zr and Y has not previously been
remarked upon to our knowledge, yet Figure 3
shows that this coherence for the Allende samples
is comparable to that between Zr and Hf. The
cause may lie in similar condensation behavior for
Zr and Y. Another possibility is that under the
highly reducing conditions under which the Allende
materials were formed (evidenced by the occur-
rence of Eu and possibly also Yb in the divalent
state), Zr was trivalent, in which case its ionic ra-
dius is very close to that of Y and the two elements
would tend to be closely associated geochemically.
Taylor, et al. (1972) have provided evidence for the
presence of trivalent zirconium in lunar rocks.
Quantitative data on the platinum-group ele-
ments (Ru, Rh, Pd, Os, Ir, Pt) could not be ob-
tained from the spark source mass spectrometer
records, because of the lack of suitable standards.
However, these elements were clearly present in
Group I and Group III samples and were not seen
in Group II and Group IV samples. Estimates
based on relative intensities would give the follow-
ing averages for Group I and Group III samples (in
ppm): Pt 10; Ir 7; Os 7; Ru 8; Rh 1; Pd 1; the
latter element appears to be depleted relative to
the other platinum-group metals, a feature prob-
ably related to its having a considerably lower
boiling point and hence being less readily con-
densed. Grossman (1973) has analyzed 16 Allende
inclusions for Ir; all except one (which belongs to
Group II from its Eu content) have Ir concentra-
tions at 5-11 ppm. Molybdenum, a comparable sid-
erophile element with a very high boiling point, is
present in all Group I and Group III samples at
a level of 4-14 ppm, is seen in two Group II sam-
ples near the lower limit of detection (0.6 ppm),
and is present in Group IV samples at about 1
ppm.
In most samples (Table 1) uranium was close to
or below the limit of detectability (0.05 ppm); how-
ever, at that level it is clearly considerably en-
riched over the chondritic mean (0.01 ppm). Ura-
10 20 n. 30
AI2O3%
40
FIGURE 2.?The relationship between CaO and A12O3 (weight percent) in individual samples.
NUMBER 19 91
nium is enriched in Groups I, II, and III, but not
in Group IV. Thorium shows a similar pattern.
Discussion
Several other investigators have published data
on minor and trace elements in materials from the
Allende meteorite, and it is of interest to correlate
their data with those presented here. Unfortu-
nately, in most instances no mineralogical or petro-
logical description accompanies the chemical data,
which makes the assignment of type (chondrule or
aggregate) uncertain. However, the large melilite
chondrules are the most prominent and most easily
extracted inclusions in the Allende meteorite, and
it is evident that sampling has been biased towards
these (as is true for the present research also).
Gast, Hubbard, and Wiesmann (1970) provided
K, Rb, Sr, Ba, and lanthanide data for what they
described as a Ca-rich inclusion from Allende. The
lanthanide distribution matches that for Group I,
as does the high Sr and Ba contents, and their ma-
terial was probably a melilite chondrule. Tanaka
and Masuda (1973) have published Ca, Al, Sr, Ba,
and lanthanide data for the Allende meteorite and
some selected components. Their Ca/Al-rich chon-
drule was a melilite chondrule, and its lanthanide
distribution pattern closely parallels that from
Group I. They analyzed two samples of a fine-
grained aggregate; the patterns are closely similar
and agree with that for Group II. An olivine
chondrule gave an unfractionated lanthanide
distribution pattern at approximately twice chon-
dritic abundance, consistent with Group IV. Only
one of their analyzed samples does not fit readily
within the grouping proposed here; their inclusion
O has a lanthanide distribution pattern rather sim-
ilar to Group III, but the negative Eu and Yb
anomalies are much less pronounced.
The most extensive set of data so far published
FIGURE 3.?The relationship between Zr and Y in individual samples.
92 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
is that of Grossman (1973) on 16 specimens of
Ca/Al-rich inclusions selected by Dr. E. A. King,
Jr., of the University of Houston. Grossman de-
termined Fe, Mn, Na, Sc, La, Sm, Eu, Yb, Co, Ir,
and Au in these specimens and on two samples of
the bulk meteorite. Through the kindness of Dr.
King, we received splits of specimens 1, 4, and 8
analyzed by Dr. Grossman. These had been se-
lected as covering a wide compositional range, and
our analyses show that sample 1 belongs to Group
I, sample 4 to Group III, and sample 8 to Group II.
Grossman's data for the remaining samples indi-
cate that they all belong to Group I.
Perhaps the most intriguing feature revealed by
the present research is the occurrence of at least
three different lanthanide distribution patterns in
the materials comprised under the description of
Ca/Al-rich inclusions. Although Groups I, II, and
III do show characteristic differences in major ele-
ment composition, these differences are relatively
much less than those for the trace elements. The
presence of marked Yb anomalies in Groups II and
III, and of a Tm anomaly in Group II appears to
be unique to these Allende materials; to our
knowledge Yb and Tm are closely coherent with
the neighboring lanthanides both in terrestrial and
in lunar materials.
It is remarkable at first glance that in Group II
a negative Eu anomaly is associated with a posi-
tive Yb anomaly, whereas in Group III a negative
Eu anomaly is associated with a negative Yb anom-
aly. However, when the Eu and Yb abundances in
individual samples in these two groups are com-
pared, one finds that the Eu/Yb ratio is relatively
constant (Table 3). Figure 1 shows that the Yb
anomaly is positive in Group II because it is
superimposed on a fractionated lanthanide pattern
with rapidly diminishing abundances of the heavier
elements, whereas it is negative in Group III be-
cause it is superimposed on an unfractionated lan-
thanide pattern in which all the other elements
(except Eu) are strongly enriched.
Thus in Groups II and III Eu and Yb show a
geochemical coherence unrelated to the other lan-
thanides. After Eu, Yb is the lanthanide most
readily reduced to the divalent state, and this pro-
vides a possible explanation for this coherence.
However, this explanation requires highly reduc-
ing conditions at some stage in the origin of Group
II and III materials, more reducing, for example,
than for lunar rocks, which show Eu anomalies but
do not have Yb anomalies. In this connection, too,
it is puzzling to find no Yb anomalies either in
Group I materials or their constituent minerals
(Mason and Martin, 1974). Boynton (1975) com-
ments that it seems unlikely that divalent Yb can
explain the Yb anomalies, since Sm is nearly as
easily reduced as Yb, and there is no evidence of
an Sm anomaly. He points out that the condensa-
tion of lanthanides from the solar nebula may be
controlled by thermodynamic equilibrium between
gas and condensed solids, and that highly fraction-
ated lanthanide patterns may result if condensates
are removed from the gas before condensation is
complete. Both Yb and Eu are predicted to be
extremely depleted in the early condensate with-
out the requirement of condensation in the diva-
lent state. According to Boynton's model, the
Group II inclusions may be a condensate from a
previously fractionated gas rather than from a gas of
solar composition. Thus the cosmochemical proper-
ties of Eu and Yb (determined by gas-solid equi-
libria) may be quite different from crystallochemical
properties (determined by liquid-solid and solid-
solid equilibria), and may allow an unambiguous
determination of which process is yielding a specific
lanthanide pattern.
The most remarkable and thought-provoking
anomaly is the positive Tm anomaly in Group II
samples. Group II samples 37 and 3598 were ana-
lyzed in 1971, when no attempt was made to meas-
ure Tm because of possible interference on the 169
mass number. In 1973 it was realized that the 169
mass number line in many Allende samples was
much too strong to be due to the multiple carbon
interference, and it was found that in Group I
samples Tm values were obtained that fell on the
smooth chondrite-normalized curve linking Er and
Yb. However, the Tm values for Group II samples
are anomalously high in comparison to Er and Yb
(Figure 1). A similar Tm anomaly in some Allende
aggregates has recently been reported by Conrad,
Schmitt, and Boynton (1975). The cause of this
Tm anomaly remains to be elucidated. Boynton
(1975) has discussed rare earth anomalies in terms
of fractional condensation in the solar nebula, and
this may be invoked as a possible cause. Another
possibility, suggested by the search for evidence for
NUMBER 19 93
the original presence of superheavy elements in the
Allende meteorite, is that the Tm excess may be a
previously unrecognized fission product.
Marvin, Wood, and Dickey (1970), who first de-
scribed the Ca/Al-rich inclusions in the Allende
meteorite, noted the general similarity between
their chemistry and mineralogy and the sequence
of compounds calculated to be among the highest
temperature condensates to form in a solar nebula.
Grossman (1972, 1973) has greatly extended this
work; he concluded (1973:1137) that the Ca/Al-
rich inclusions in the Allende meteorite are en-
riched in Sc, Ir, and the lanthanides by a factor of
22.8 ? 2.2 relative to Type I carbonaceous chon-
drites, and that the large enrichments of these
refractory trace elements provided strong evidence
that the inclusions are high-temperature conden-
sates from the solar nebula. All but two of the
samples he analyzed belong to Group I, and his
conclusion appears well-founded for this group.
Can this conclusion be extended to Groups II and
III, or do they have a different origin? The trace
element distribution in the Group III samples is
not greatly different from Group I, except for the
negative Eu and Yb anomalies in the lanthanide
distribution, and these two groups may well be
genetically related. However, the strongly fraction-
ated lanthanide distribution in Group II samples,
the Eu, Tm, and Yb anomalies, and their relative
depletion in other refractory elements such as Zr,
Mo, and the platinum metals, strongly suggest ex-
tensive chemical differentiation of their parent ma-
terial.
One aspect still insufficiently explored is the
possible correlations between mineralogy, texture,
and chemistry of the Allende inclusions. Group I so
far comprises only melilite-rich chondrules; Group
II comprises four aggregates and one chondrule;
the two representatives of Group III are both ag-
gregates; Group IV comprises the common olivine-
rich chondrules, but also includes some aggregates.
The term aggregate covers a variety of fine-grained
white, pink, or pale gray inclusions with irregular
form; if an aggregate approaches spherical form,
the distinction between aggregate and chondrule
may be arbitrary. The form of the aggregates and
their contacts with the enclosing matrix vary
greatly; some are angular fragments with sharp
contacts, many are irregular in form, with intricate
mossy-like margins against the matrix, others are
elongated shards or stringers. Subparallel elonga-
tion of the latter type in a hand specimen often
indicates a vaguely oriented fabric, suggesting an
original flattening during deposition (as plastic glass
fragments?) or a secondary flattening produced by
later deformation. The overall impression is that
some aggregates may be devitrified glass fragments,
whereas others represent agglutinated dust particles.
The formation of chondrules, specifically the
melilite-rich chondrules of Group I, presents an ad-
ditional problem. Grossman's condensation curves
(1972) are for gas-solid equilibria, and if the Group
I material originated in this way, it should have
separated as a dust; the formation of chondrules
involved segregation of this dust and subsequent
melting, by such processes as lightning or shock ef-
fects. Alternatively, these chondrules may have orig-
inated in some nonequilibrium process, such as that
suggested by Blander and Katz (1967): metastable
nucleation of liquid droplets, formed by super-
saturation of the nebular gas, component by com-
ponent, as subcooling took place below the
temperatures where equilibrium solids should have
crystallized out.
TABLE 3.?Abundances (ppm) of Eu and Yb in Group H and Group m samples, and the Eu/Yb
ratios
Elements
Eu . . . .
?&,....
Eu/Yb ? .
0
0
0
37
.31
.51
.62
3598
0.18
0.84
0.21
Group II
3803
0.17
0.73
0.23
4691
0.62
1.6
0.39
4692
0.13
0.37
0.35
Group
3593
0.36
1.9
0.17
III
4698
0.25
0.74
0.34
94 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
The mineralogy and chemistry of the Group I
materials certainly support the concept that they
represent an early high-temperature condensate.
The condensation sequence established by Gross-
man shows that this would be followed by forsteritic
olivine and enstatite, essentially the material of the
Group IV chondrules and aggregates. The position
of the Group II and Group III materials in this
sequence is more enigmatic. In minor and trace-
element concentrations, Group III materials are
not very different from Group I, the most marked
feature being the negative Eu and Yb anomalies.
In view of the small number of Group III speci-
mens, further speculation on their origin may be
deferred. Group II materials are in marked con-
trast to Groups I and III in minor and trace
elements, with relatively high alkalies, low refrac-
tories (Zr, Hf, Mo, and platinum metals), and
especially the strongly fractionated lanthanide pat-
tern. Evidently the medium from which this ma-
terial condensed had undergone or was undergoing
considerable fractionation of these elements. So far
a complementary condensate, enriched in the heav-
ier lanthanides, has not been identified; however,
since Group II material forms only a small amount
of the total meteorite (probably about 5% or less),
the complementary enriched material may be too
dispersed to be recognizable. Possibly Group II ma-
terials represent a late condensate, subsequent to
the segregation of Group I and Group IV. The
Group IV material is almost entirely magnesium-
iron silicates; separation of this material from the
parent medium would enrich the latter in other
major elements, among which would be Ca, Al, and
the alkalies. Since olivine is a poor host for most
trace elements, these too would remain in the par-
ent medium and increase in concentration. Pyrox-
ene is a mineral which preferentially concentrates
the heavier lanthanides, and its separation along
with olivine would lead to a depletion of these
elements in the residual material. In this connec-
tion the composition of interstitial glass in the
olivine-pyroxene chondrules reported by Clarke,
et al. (1971) is revealing; this glass composition is
(weight percent) SiO2, 47.8; A12O3, 24.7; FeO, 0.7;
MgO, 6.3; CaO, 17.5; Na2O; 2.0; K2O, 0.2, a com-
position similar in many respects to the bulk com-
position of Group II aggregates.
This discussion thus suggests at least two periods
of segregation for the Ca/Al-rich inclusions, one
before the separation of olivine and one following
it. Much additional work needs to be done to verify
this, and to fill out the details of the process.
Clearly, however, the Allende meteorite preserves
a remarkable record of the origin of chondrules
and chondrites, but one which requires extensive
and intensive research to decipher.
Literature Cited
Ahrens, L. H., and H. von Michaelis
1969. The Composition of Stony Meteorites, III: Some
Inter-element Relationships. Earth and Planetary
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Blander, M., and J. L. Katz
1967. Condensation of Primordial Dust. Geochimica et
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Boynton, W. V.
1975. Fractionation of the Solar Nebula: Condensation of
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Clarke, R. S., Jr., E. Jarosewich, B. Mason, J. Nelen, M.
Gomez, and J. R. Hyde
1971. The Allende, Mexico, Meteorite Shower. Smithson-
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Conrad, R. L., R. A. Schmitt, and W. V. Boynton
1975. Rare-Earth and Other Elemental Abundances in
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Gast, P. W., N. J. Hubbard, and H. Wiesmann
1970. Chemical Composition and Petrogenesis of Basalts
from Tranquillity Base. Proceedings of the Apollo
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Graham, A. L., and B. Mason
1972. Niobium in Meteorites. Geochimica et Cosmochimica
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Gray, C. M., D. A. Papanastassiou, and C. J. Wasserburg
1973. Primitive "Sr/^Sr in the Allende Carbonaceous
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1972. Condensation in the Primitive Solar Nebula. Geo-
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Marvin, U. B., J. A. Wood, and J. S. Dickey, Jr.
1970. Ca-Al Rich Phases in the Allende Meteorite. Earth
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In press. Meteorites. Chapter B-l in The Data of Geo-
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Mason, B., and P. M. Martin
1974. Minor and Trace Element Distribution in Mellilite
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Zellmer, and R. A. Schmitt
1974. Elemental Composition of Individual Chondrules
NUMBER 19 95
from Carbonaceous Chondrites, Including Allende.
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Tanaka, T., and A. Masuda
1973. Rare-Earth Elements in Matrix, Inclusions, and
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The St. Mary's County, Maryland, Chondrite
Albert F. Noonan, Eugene Jarosewich, and Roy S. Clarke, Jr.
ABSTRACT
The St. Mary's County, Maryland, meteorite fell
on an afternoon in June of 1919. One individual
stone of perhaps 500 grams is known to have been
recovered, but only a 23.4 gram fragment was
preserved. A 2.9 gram piece was made available
for laboratory investigations.
Chemical parameters determined from the bulk
chemical analysis, compositions of the major sili-
cates, and the overall texture of the meteorite
show it to be an LL3_chondrite. The average
compositions of oliyine, Fa 14.4 (Fa, 0.2-76.6), and
low-Ca pyroxene, Fs 9.9 (Fs, 0.5-37.5), with %MD's
of 51.9 and 67.3, respectively, show that this meteor-
ite is among the least equilibrated of the ordinary
chondrites. Calcium and manganese concentrations
in olivine plotted against fayalite content show
mixing of an Fe-rich matrix fraction with one and
possibly two chondrule fractions. Oxide plots of
minor elements in low-Ca pyroxene (<1% CaO)
suggest a general increase in chromium, manganese,
and possibly calcium and aluminum concentration
with increasing iron content.
Introduction
A bright fireball accompanied by a lingering
smoke trail and a series of violent detonations that
shook buildings and windows over a wide area
announced the fall of the Saint Mary's County,
Maryland, meteorite to hundreds of residents of
tidewater Virginia and Maryland on a June after-
noon in 1919. It approached from the southwest
at about 4 PM, attracting the attention of retired
Albert F. Noonan, Eugene Jarosewich, and Roy S. Clarke, Jr.,
Department of Mineral Sciences, National Museum of Natu-
ral History, Smithsonian Institution, Washington, D. C. 20560.
sea-captain John Forrest, who was working in a
tobacco field adjoining his home along St. Jerome
Creek, near the village of Ridge, St. Mary's County,
Maryland. An object that later proved to be a
meteorite struck the ground approximately 20 feet
[6 m] from where he stood, producing a cloud of
dust. Captain Forrest removed the stone from the
ground, and believing it to be hot carried it on his
hoe to the house. This meteorite specimen, most of
which has since been lost, was the only one recov-
ered. The recovery site (approximately SS'^IO'N,
76?23/W) is on a peninsula between the Potomac
River and the Chesapeake Bay, and it was felt at
the time that other specimens may have landed in
the adjoining waters, particularly in the Chesa-
peake Bay. The exact date of fall is not known, but
it was within a few days of 20 June 1919.
The main mass of the meteorite, probably some
500 grams or more, remained at Captain Forrest's
home serving as a doorstop, and his widow and son
reported seeing it as late as 1933. Since that time,
however, it has disappeared without a trace, and
all of the people involved with the recovery have
left the area. The surviving piece was broken off
the main mass by Captain Forrest within a few
days of the fall and was given to William Matthews
of Great Mills, Maryland. This 24.25 gram speci-
men came into the possession of Matthews' grand-
son, Francis D. Cecil, who later loaned it to the
Maryland Academy of Sciences, Baltimore, Mary-
land. The fragment was shown to Dr. William F.
Foshag of our staff and identified as a meteorite in
1937. The recovery of the meteorite and a descrip-
tion of the surviving specimen have been recorded
by Mather (1938, 1954) and Cecil (1944).
Early in 1969 the pyramidal specimen, fusion-
crusted on three of its four sides, was borrowed
96
NUMBER 19 97
from the Maryland Academy of Sciences through
the courtesy of Paul S. Watson. The specimen
weighed 23.4 grams when it was received at the
Smithsonian Institution. It was photographed, a
model was made, and a 2.9 gram piece was removed
for analysis. A polished section and two polished
thin sections were prepared for optical and
elecron-microprobe examination (NMNH 5423),
and the remaining material was used for a bulk
chemical analysis. A 19.7 gram piece was returned
to the Maryland Academy of Sciences.
Texture
The St. Mary's County meteorite is a black,
matrix-rich chondrite of low petrographic type
(Figure 1). In thin section (0.03 mm), the ma-
trix is opaque and contains small angular sili-
cate crystals and finely dispersed metal and sulfide
particles. The predominant inclusions are broken
and intact olivine and/or low-Ca pyroxene chon-
drules, which range up to 0.6 mm in diameter.
These frequently contain primary albitic glass and
metal droplets. In addition, several metal-sulfide
chondrules were observed, but these phases usually
occur in chondrule rims and as small inclusions in
chondrules and in the matrix.
FIGURE 1.?Overall chondritic texture of the St. Mary's
County (LL3) meteorite; length of specimen, 19 mm.
Chemistry
The bulk chemical analysis of the St. Mary's
County meteorite is presented in Table 1. It was
performed on a 1.5 gram sample that appeared to
be reasonably representative of the 23.4 gram speci-
men. The procedures of Jarosewich (1966) were
used with the modification that the portion taken
for major constituent analysis was completely dis-
solved, rather than analyzing an acid-soluble and
acid-insoluble fraction. The carbon content is high
compared to other unequilibrated ordinary chon-
drites; only Sharps is reported to have a higher
carbon concentration of 0.95% (Fredriksson,
Jarosewich, and Nelen, 1969). The SiO2/MgO ratio
of 1.64 is typical of ordinary chondrites and the
Fe/SiO2 and Fe?/Fe ratios of 0.50 and 0.14 are
within the range recognized for LL-group chon-
drites (Van Schmus and Wood, 1967).
TABLE 1.?Chemical analyses of the St. Mary's County
chondrite
Constituent A
Fe
Ni
Co
FeS
SiO2
TiO2
A12O3
FeO
MnO
MgO
CaO
Na2O
K2O
P2O5
H2O(+)
H2O(-)
Cr2O3
C
Total
2.75
1.14
0.04
6.53
40.45
0.14
2.08
17.28
0.33
24.71
1.86
0.97
0.10
0.16
N.D.
0.27
0.55 v
0.57
99.93
Total Fe 20.33
Constituent B
H
C
0
Na
Mg
Al
Si
P
S
K
Ca
Ti
Cr
Mn
Fe
Co
Ni
Total
0.03
0.57
37.58
0.72
14.90
1.10
18.89
0.07
2.38
0.08
1.33
0 = 08
0.38
0.26
20.33
0.04
1.14
99.88
Constituent C
Na
Mg
Al
Si
P
K
Ca
Ti
Cr
Mn
Fe
Co
Ni
Total
1.21
25.12
1.85
31.84
0.12
0.13
2.24
0.13
0.64
0.44
34.27
0.07
1.92
99.98
CHEMICAL PARAMETERS
SiO2/MgO =1.64
Fe/SiO2
Fe?/Fe
= 0.50
= 0.14
A = Bulk chemical analysis by E. Jarosewich
B = Elemental composition
C=Volatile-free (less 0, C, H and S)
Fe?/Fe=metallic Fe/total Fe.
Mineralogy
The analyses of the St. Mary's County silicates
were made with the ARL microprobe model SEMQ,
utilizing an accelerating potential of 15 KV and a
beam current of 0.15 \iA. Results have been cor-
rected using procedures outlined by Bence and Al-
bee (1968) and the correction factors of Albee and
Ray (1970). Two spots separated by a 1-2 micron
spacing were counted for 10 seconds and averaged
for each analyzed area. An advantage of our micro-
probe is that nine elements can be determined
simultaneously, thus providing minor element data
from spots that are analyzed for major elements.
98 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
OLIVINE
Olivine was analyzed for Si, Al, Fe, Mg, Ca, K,
Na, Cr, and Mn. The primary mineral standard
used for major element determinations was Spring-
water olivine with 13.26% Fe. The minor elements
calcium and manganese were determined using
An 80 and Rockport fayalite with 11.64% Ca and
1.30% Mn, respectively. Springwater olivine was
analyzed routinely every twenty samples to provide
an internal check on instrument stability. Iron
concentrations of those analyses with oxide sum-
mations between 98%?101% were applied to a cal-
culated calibration curve to establish the fayalite
content of each well-analyzed grain.
A total of 269 olivine analyses were made, which
includes analyses of crystals from 137 separate
chondrules and 82 matrix crystals. For all olivine
analyses, the average iron content (Fe) is 10.4%,
the average fayalite content (Fa) is 14.4 (range, Fa,
0.2-76.6) and the percent mean deviation (%MD) is
51.9. (The %MD is the parameter used by Dodd,
Van Schmus, and Koffman, 1967, as an index of
olivine and pyroxene heterogeneity.) These results
compare well with the interpretation of an x-ray
diffractometer trace of the meteorite in which the
0.7CU
0.60
0.50
CI XTLS IN METRL-RICH CHOND
A XTLS IN METRL-POOR CHOND
+ MRTRIX CRYSTRLS
- ZONED CRYSTRLS
0.00
10 15 20 25 30
MOLE PCT. FRYRLITE 35 40 45 50
FIGURE 2.?Plot of CaO concentration vs fayalite content of olivine (lines join compositions in
zoned crystals). Note particularly the high to low CaO values of the Mg-rich olivine in metal-
rich chondrules, possibly representing a separate chondrule fraction, and the relatively Fe-rich
fragments from the matrix. Only one olivine fragment from the matrix with the composition
Fa 76.6 and containing 0.14% CaO is not represented in the plot.
NUMBER 19 99
olivine peak (130) indicates a broad range in com-
position from Fa 0 to Fa 80 with a small peak at
Fa 12 (B. Mason, pers. comm.). The shape of the
peak shows that most of the olivine is Mg-rich, in
the range Fa 0-15, with diminishing amounts of
more Fe-rich material. Compared with olivine com-
positions from other unequilibrated chondrites
(Dodd, Van Schmus, and Koffman, 1967), St. Mary's
County is clearly the least equilibrated of the
ordinary chondrites. Although the major element
analyses and x-ray diffraction data are useful for
classification purposes, they do not provide clues
as to the number or origin of olivine fractions
that may exist in a particularly unequilibrated
chondrite like St. Mary's County, information
which may become apparent with minor element
data.
When CaO and MnO concentrations in olivine
from relatively metal-rich and metal-poor chon-
drules and from silicate fragments in the matrix
are plotted against fayalite content (Figures 2 and
3), at least two important points become apparent.
Firstly, silicate inclusions in the matrix are not
simply fragments of crushed chondrules. The
olivine has a mean fayalite content of 21.2, which,
if the silicates are of primary composition, cannot
0.5C1
0.40..
? XTLS IN METRL-RICH CHOND
A XTLS IN METRL-POOR CHOND
-I- MRTRIX CRYSTRLS
- ZONED CRYSTRLS
0.30.-
0.20..
Q_
0.10..
0.00
10 15 20 25 30
MOLE PCT. FRYRLITE 35
40 45 50
FIGURE 3.?Plot of MnO concentration vs fayalite content of olivine. Only one olivine fragment
from the matrix with the composition Fa 76.6 containing 0.46% MnO is not represented in
the plot.
100 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
be derived solely from the metal-rich and metal-
poor chondrule olivine with mean fayalite contents
of 3.0 and 14.1, respectively. Indeed, several abraded
chondrules with forsteritic olivine adjacent to
matrix material suggest that all silicates do reflect
primary compositions. Therefore, although sili-
cates in the matrix may include olivine fragments
derived from chondrules similar in composition to
those studied, it must contain a separate Fe-rich
olivine fraction. Secondly, olivine in metal-rich
chondrules is enriched in Ca and depleted in Mn
relative to olivine in metal-poor chondrules, possi-
bly suggesting two separate chondrule fractions.
The high-Ca olivine is Mg-rich (Fa, 0-10), occurs
predominantly in metal-rich chondrules, and trends
from a high of 0.67% CaO for nearly pure forsterite
to below 0.10% CaO at about Fa 10 (Figure 2).
This grouping corresponds to the proposed high-
temperature metal-rich chondrule fraction in
Sharps (Dodd, 1971). This fraction is depleted in
MnO but shows a positive rather than a negative
correlation with fayalite content, also to about
Fa 10 (Figure 3). Olivine with greater than about
8% Fa (Fa 10), which includes most metal-poor
chondrules and silicate fragments from the matrix,
shows no correlation of either CaO or MnO con-
centration with fayalite content.
Most of the compositional zonation displayed in
1 .00,.
0.80..
? XTLS IN METflL-RICH CHOND
A XTLS IN METRL-POOR CHOND
+ MRTRIX CRYSTflLS
- ZONED CRYSTflLS
0.60..
A
A A
0.40..
Q_
0.20..
0.00
A
10 15 20 25 30HOLE PCT FERROSILITE
FIGURE 4.?Plot of MnO vs ferrosilite content of low-Ca pyroxene (< 1% CaO) suggests an in-
crease in manganese with increasing iron (lines join compositions in zoned crystals).
NUMBER 19 101
these olivines is normal, with Mg-rich cores and
relatively Fe-rich rims. One single crystal metal-poor
chondrule, however, was observed with a core of
Fa 6.2 and a rim of Fa 0.2.
PYROXENE
Pyroxene was analyzed for Si, Al, Fe, Mg, Ca, K,
Mn, Ti, and Cr. The primary mineral standards
used for pyroxene analyses were Johnstown hyper-
sthene (Si, 25.06%; Fe, 12.14%; Mg, 16.40%) and
an omphacite standard (Al, 4.71%; Ca, 9.83%). The
more abundant minor elements, manganese and
chromium, were determined using Rockport fayal-
ite (Mn, 1.30%) and a chromite standard (Cr,
40.00%). Johnstown hypersthene was analyzed every
twenty samples to provide a check on instrumental
drift, which was negligible. Iron concentrations of
the low-Ca (<1% CaO) pyroxenes with oxide sum-
mations between 97%?101% were applied to a
calculated calibration curve to establish the fer-
rosilite content of each grain.
A total of 274 separate analyses were made of
pyroxene in 23 metal-rich and 67 relatively metal-
poor chondrules and from 101 silicate fragments in
the matrix. Of these, 222 analyses are of the more
abundant low-Ca (<1% CaO) pyroxene, mostly
clinoenstatite and clinobronzite, and 52 analyses
1 -OCU
? XTLS IN METRL-RICH CHOND
A XTLS IN METRL-POOR CHOND
+ MRTRIX CRYSTRLS
- ZONED CRYSTRLS
0.20
0.00 0.20 0.40NT. PCT. MNO 0.60 0.80 1 .00
FIGURE 5.?Binary oxide plot of Cr2O, vs MnO suggests that chromium increases as does
manganese with increasing iron content of pyroxene (cf. Figure 4).
102 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
of more calcic pyroxene (1-18% CaO), which oc-
curs both as fragments in the matrix and as rims on
chondritic low-Ca pyroxene. The average iron
content (Fe) of the low-Ca pyroxene is 5.2%, the
average ferrosilite content (Fs) is 9.9 (range, Fs
0.5-37.5) and the percent mean deviation (%MD) is
67.3, which is a significantly higher value than has
been reported for other unequilibrated ordinary
chondrites (Dodd, Van Schmus, and Koffman, 1967).
As with the olivine analyses, iron determinations
are useful for classification purposes and compara-
tive studies, but minor element data may help dis-
tinguish possible pyroxene fractions.
Binary oxide plots were prepared of A12O3, CaO,
MnO, and Cr2O3 values against ferrosilite content
of low-Ca pyroxene. When MnO concentrations
are plotted against ferrosilite content (Figure 4),
it becomes evident that pyroxene from metal-rich
chondrules is Mg-rich and low in MnO relative to
both fragments in the matrix and metal-poor
chondrule pyroxene. But unlike the olivine, both
the Mg-rich fraction and the pyroxene in metal-
poor chondrules and the matrix overlap to a large
measure and show a continuous positive correla-
tion of MnO with ferrosilite. Therefore, the
pyroxene data provides no compelling evidence to
suggest that metal-rich chondrules and metal-poor
chondrules represent two distinct chondrule frac-
tions although that possibility may be supported
by the olivine data. Also of interest in the MnO vs
Fs plot is the extensive mixing of points repre-
senting matrix analyses (Fs = 9.8) with pyroxene
analyses from both metal-rich (Fs = 3.0) and metal-
poor (Fs = 12.6) chondrules. The pyroxene frag-
ments in the matrix clearly could be fragments of
pyroxene derived from chondrules similar to the
compositions studied.
Of the other minor elements determined, a
Cr2O3 vs MnO binary plot shows that a positive
correlation exists (Figure 5), both elements appar-
rently increasing in concentration with Fe. No clear
trends are apparent for Al or Cr against ferrosilite
content. However, Cr2O3 against CaO and A12O3
plots show a subtle positive correlation suggesting
that calcium and aluminum also increase in concen-
tration to some degree with increasing iron.
LESS ABUNDANT MINERALS
The less abundant minerals identified in the St.
Mary's County meteorite include small amounts of
taenite, kamacite, troilite, and chromite, and minor
amounts of plagioclase, pentlandite, copper, spinel,
and a phosphate mineral, probably whitlockite.
The feldspathic fraction occurs both as primary
albitic glass, which is commonly found in ordinary
chondrites, and as crystalline calcic plagioclase.
Two abraded fragments were found to contain
twinned plagioclase with compositions in the range
An 80-83, which occur with low-Ca, Fe-Mg silicates.
Both fragments appear equally medium-grained;
however, one occurs with equilibrated olivine (Fa
13) and pyroxene (Fs 12) while the other contains
less equilibrated and higher iron silicates with com-
positions in the range Fa 23-25 and Fs 15-18 for
olivine and pyroxene, respectively. One plagioclase
matrix fragment was found with a composition
An 26.
The most commonly occurring opaque minerals
are troilite, taenite, and kamacite. Typical of most
unequilibrated ordinary chondrites and some car-
bonaceous chondrites, globular metal grains or
chondrules rimmed with troilite were observed.
The taenite in these features contains from 30%-
50% Ni and frequently displays the familiar M-
shaped Ni-concentration profile when in contact
with kamacite. Two pentlandite grains with 16%
Ni were found in troilite with taenite and kamacite
and presumably represent disequilibrium assem-
blages, which are not often found in unequilibrated
ordinary chondrites (Dodd, Van Schmus, and Koff-
man, 1967). In addition to the large inclusions,
metal also occurs in small, occasionally sulfide-
rimmed droplets in glassy chondrules. Scanning-
electron pictures of Na, Ca, and P distribution in
these 10 micron and less diameter features suggests
that phosphate nucleation, probably whitlockite,
has occurred at the metal-silicate interface, or, if
rimmed with sulfide, at the metal-sulfide interface.
Literature Cited
Albee, Arden L., and L. Ray
1970. Correction Factors for Electron Probe Microanalysis
of Silicates, Oxides, Carbonates, Phosphates, and
Sulfates. Analytical Chemistry, 42:1408-1414.
Bence, A. E., and A. L. Albee
1968. Empirical Correction Factors for the Electron
Microanalysis of Silicates and Oxides. Journal of
Geology, 76:382-403.
Cecil, Francis D.
1944. The St. Mary's Meteorite of 1919. Sky and Tele-
scope, 3(12):9.
NUMBER 19 103
Dodd, R. T., Jr.
1971. The Petrology of Chondrules in the Sharps Mete-
orite. Contributions to Mineralogy and Petrology,
31:201-227.
Dodd, R. T., Jr., W. R. Van Schmus, and D. M. Koffman
1967. A Survey of the Unequilibrated Ordinary Chon-
drites. Geochimica et Cosmochimica Acta, 31(6):921-
951.
Fredriksson, K., E. Jarosewich, and J. Nelen
1969. The Sharps Chondrite?New Evidence on the Origin
of Chondrules and Chondrites. Pages 155-165 in
P. Millman, Meteorite Research. Dordrecht: D.
Reidel Publishing Company.
Jarosewich, E.
1966. Chemical Analysis of Ten Stony Meteorites. Geo-
chimica et Cosmochimica Acta, 30:1261-1265.
Mather L. Bryant, Jr.
1938. A New Meteorite from Maryland. The Natural His-
tory Society of Maryland Bulletin, 8(8)-.63-68.
1954. Maryland Meteorites. Maryland Naturalist, 24(1-
4):2-18.
Van Schmus, W. R., and J. A. Wood
1967. A Chemical-petrologic Classification for the Chon-
dritic Meteorites. Geochimica et Cosmochimica Acta,
31:747-765.
Mineralogical and Chemical Compositions of
Silicate Inclusions in the El Taco,
Campo del Cielo, Iron Meteorite
Frank Wlotzka and Eugene Jarosewich
ABSTRACT
The silicate minerals in these inclusions (olivine,
orthopyroxene, diopside and a sodic plagioclase)
have the same composition as silicates in chon-
drites except for a lower FeO-content of the mafic
minerals and a lower K-content of the feldspar.
Small grains of K-feldspar occur with the plagio-
clase. Olivine contains 3.5% to 4.5% FeO, ortho-
pyroxene 3.8% to 4.6% FeO. The range of composi-
tions within one inclusion is smaller, however, and
distinct differences in mean FeO-content occur
between different inclusions; the fayalite to fer-
rosilite ratio varies from inclusion to inclusion.
The outer zone of olivine and pyroxene grains is
depleted in iron oxide compared to the central part.
Thus three types of disequilibria occur: (1) dis-
equilibrium between different inclusions, (2)
disequilibrium between olivine and pyroxene in a
given inclusion, and (3) disequilibrium within
single olivine and pyroxene grains. Both the min-
eral composition and the bulk chemistry of the
silicate part of the inclusions are close to normal
chondrites, if compared on an iron-free basis.
Variations that do not seem to be caused by
nonrepresentative sampling are found between dif-
ferent inclusions. The variations affect mainly the
elements Ca, Al, and the alkalies. They can be
explained by the removal of diopside and/or feld-
spar from a chondritic material, perhaps through
partial melting. Other features suggest that the
lower iron content of the mafic minerals was pro-
duced by reduction of chondritic silicates.
Frank Wlotzka, Max-Planck-Institut fur Chemie, Mainz,
Germany. Eugene Jarosewich, Department of Mineral
Sciences, National Museum of Natural History, Smithsonian
Institution, Washington, D.C. 20560.
Introduction
The El Taco meteorite is one of the Campo del
Cielo, Argentina, irons. It was recovered by an
expedition described by Cassidy, et al. (1965). The
El Taco specimen, which weighed 2000 kg, was cut
at the Max-Planck-lnstitut fur Chemie at Mainz,
Germany (Hintenberger, Schultz, and Weber, 1969).
Three cuts were made parallel to the longest axis
of the meteorite, so that two slices of about 2 cm
thickness and two end pieces resulted. One of the
slices (slice A, Figure 1) is on exhibit in the
Meteorite Hall of the National Museum of Nat-
ural History, and the other (slice B) was made
available for research by the Max-Planck-Institut
fiir Chemie, Mainz.
Slice A revealed a large number of silicate inclu-
sions (Figure 1). One inclusion of this kind had
already been found in the El Toba specimen of
Campo del Cielo and described by Park, Bunch,
and Massalski (1966). Silicate inclusions are known
from other iron meteorites, for instance, Linwood
(Henderson and Perry, 1949), Woodbine (Mason,
1967), Netschaevo (Olsen and Jarosewich, 1971),
and Odessa (Marshall and Keil, 1965). A thorough
description of the mineral compositions of the
silicate inclusions from most of the iron meteorites
known to contain them was given by Bunch, Keil,
and Olsen (1970). All these iron meteorites (except
Netchaevo) belong to the same chemical group IAB
ofWasson(1970).
In continuation of earlier work (Wlotzka and
Jarosewich, 1969), this paper describes the miner-
alogy and the bulk chemical composition of a
104
NUMBER 19 105
FIGURE 1.?El Taco slice A, etched. Silicate inclusions appear black. Long axis of section, 111 cm.
106 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
number of the El Taco silicate inclusions in more
detail, with special emphasis on possible variations
between different inclusions.
ACKNOWLEDGMENTS.?We wish to thank Profes-
sor Hintenberger for providing a facility for an
ingenious cutting of this large specimen of the
El Taco meteorite, Dr. H. Wanke and Dr. K.
Fredriksson for their stimulating discussions, Mr.
R. S. Clarke for selecting and providing some
samples, and Dr. B. Mason for his suggestions in
the preparation of the manuscript. One of us
(F. W.) wishes to thank the members of the Depart-
ment of Mineral Sciences of the Smithsonian
Institution for their hospitality and help during
his stay there, especially Mrs. P. R. Brenner, Mrs.
C. Trice, Mr. C. Obermeyer, Mr. J. Nelen, and
Mr. A. F. Noonan. We also thank Mr. G. Moreland
for the preparation of excellent polished thin sec-
tions. The completion of this study was made
possible through a special fund provided by the
Secretary of the Smithsonian Institution.
Macroscopic Features
Campo del Cielo is a coarse octahedrite. Figure 1
shows the Widmanstatten pattern of the etched
slice. The silicates are scattered over the whole area
of the sectioned slice. Most of them are located at
grain boundaries of the primary taenite crystals,
but several appear also in the centers of these
FIGURE 2.?Silicate inclusions of slice A.
NUMBER 19 107
crystals. About nine different primary taenite crys-
tals can be recognized in slice A (Figure 1). There
is no disturbance of the Widmanstatten structure,
i.e., flow or shock features, visible either around
the silicates or in other parts of the metal areas,
as has been reported for smaller Campo del Cielo
specimens by Bunch and Cassidy (1968). This indi-
cates clearly that these inclusions were incorporated
into the metal before the taenite-kamacite trans-
formation took place, or at temperatures above
about 750? C.
The outline of most of the silicate inclusions is
angular with usually straight margins. This is sug-
gestive of a fragmental nature of these inclusions.
It can be noted, however, that several of the
straight boundaries are parallel to kamacite laths
in the Widmanstatten pattern and may be second-
ary features. This point is difficult to prove, and
most observers fail to see it. It seems, however,
that some of the silicate-metal boundaries and
indentations in the silicate inclusions are controlled
by the Widmanstatten pattern or the growth direc-
tions of the kamacite laths. Examples are shown
in Figure 2. The microscopic texture of the sili-
cates shows replacement of silicates by opaques
(mostly by graphite, which also seems to replace
troilite and metal) in many places, which could
explain such a reshaping of the silicate inclusions.
In contrast to other iron meteorites with silicate
inclusions, for instance, Woodbine (Mason, 1967),
no swathing kamacite is found around the inclu-
sions of El Taco. Macroscopically the inclusions
differ in the relative amounts of graphite and
opaques and in the grain size of the silicates.
cutting lines
FIGURE 3.?Line drawing of part of El Taco slice B. Silicate inclusions are hatched. Open bars
in inclusions 2 and 3 give locations of samples taken for chemical analysis, lines 1, 3, 4, 7,
and 9 give locations of the corresponding polished thin sections. Inclusion 6 was a veinlike
inclusion which was exposed along the indicated cutting line and from which section 6 was
made. Width of cut, 6 cm.
108 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
Sampling
Inclusion 1 was taken from the surface of El
Taco. A piece of 3.5 grams was used for chemical
analysis; from another piece, polished thin section
(PTS) 2 was made. Inclusions 2 and 3 were ob-
tained from the research slice B, and their loca-
tions and the sampling are shown in Figure 3. PTS
6 was made from a small inclusion (No. 6, Figure
3). Additional thin sections were made from in-
clusions that were exposed during the cutting
of slices A and B. These are: location A 1-5/6:
inclusion 4, PTS 10; location A-15/18: inclusion 5,
PTS 5; location A 1-4/7: inclusion 8, PTS 8; loca-
tion B III-II/7: inclusion 12, PTS 12; and location
not known: inclusion 11, PTS 11.
Microscopic Texture
Between the metal host and the silicate inclusion,
a border zone consisting of schreibersite, troilite,
and graphite is found. Figure 4 shows an example:
schreibersite usually forms a thin band against the
metal, followed and partly replaced by troilite and
graphite. In some places a very fine-grained eutec-
toid intergrowth of metal and troilite and/or
sphalerite is found. The same type of border zone
was described by Park, Bunch, and Massalski (1966)
for the El Toba silicate inclusion.
The silicate portions of the inclusions differ
considerably in grain size and distribution of
opaques and each inclusion has its own texture.
Two main types of textures can be distinguished:
(1) large silicate crystals set in a matrix of graphite
or sometimes troilite and metal (Figure 5), and
(2) allotriomorphic intergrowths of smaller, equi-
granular grains (Figure 6).
The textural relationships of the opaque min-
erals graphite, troilite, and metal with one another
and with the silicates are more complex and will
be described in a separate paper (Wlotzka, in prep.).
The conclusions of this study are that graphite is
a late addition in these inclusions and replaces
metal, troilite, and silicates in the texture of type
1 mentioned above. In type 2, graphite (if present)
occurs as small flakes dispersed throughout the sili-
cates and does not show tendencies to form veins
like in type 1 (Figure 7).
In contrast to mesosiderites and many chondrites
and achondrites no brecciation structure is found.
The silicates have an igneous texture, and the equi-
FIGURE 4.?Border zone between metal host and silicate in-
clusion 8, reflected light. (M = metal, S = schreibersite, T =
troilite, G = graphite, with some rounded silicate grains in
the lower part, width of image = 1.5 mm.)
granular and allotriomorphic intergrowth suggests
a metamorphic recrystallization. Graphite and some-
times metal veins fill cracks in the silicate fragment
in some places. Only in one thin section a straight
boundary between two different kinds of structures
or "fragments" was found; all other sections studied
appear to be homogeneous throughout, except for
the development of a coarser texture towards the
metal host, with euhedral silicate crystals in a
graphite or troilite matrix.
Table 1 gives the main minerals found in three
different inclusions and their relative amounts as
determined by point counting. Noteworthy are the
large variations in the relative amounts of the
opaque minerals graphite, troilite, and metal.
Where graphite is high, troilite is low, and vice
versa. Thus the sum of the opaques and conse-
NUMBER 19 109
FIGURE 5.?Coarse silicate texture, inclusion 8: a, transmitted light (black areas are graphite),
note graphite "nibbling" at silicate grains; b, reflected light, crossed polarizers.
quently of the silicates is rather constant. It is
interesting that the amount of silicates in these
three inclusions of 75.9%, 77.3%, and 74.5% is
quite close to the average silicate portion of H-
chondrites, which is 76% (Table 7). The silicate
portion of two of the three inclusions analyzed
chemically is higher, but this does not give the true
silicate amount, as coarse metal particles were
removed prior to analysis.
In addition to the main minerals listed in Tables
1 and 2, the following accessory minerals were
found: schreibersite and cohenite (at the border to
the metal host), apatite, chromite, and sphalerite.
The apatite is a chlorapatite; the microprobe
analysis of 11 grains in different sections gave an
average (in weight percent) of CaO, 52.6; P2O5;
41.1; Cl, 6.00; FeO, 0.30; MgO, 0.11; Na2O, 0.46;
F is not determined, sum 99.2 (corrected for
Cl = 0). This is smiliar to the composition of the
Campo del Cielo apatite published by Bunch, Keil,
and Olsen (1970). The silicates often contain small
inclusions, mostly troilite or metal. Veining with
iron oxides formed by terrestrial weathering is
found in most specimens.
Mineral Composition
In Table 2 the orthopyroxene, olivine, diopside,
plagioclase, and K-feldspar compositions are given
for one inclusion as determined by standard pro-
cedures with an ARL SEMQ microprobe. The
results were corrected by the method of Bence and
Albee (1968). During the study of these inclusions
it was found that small differences in the Fe/
110 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
FIGURE 6.?Fine silicate texture, inclusion 5: a, transmitted light (black vein in upper left is
graphite); b, reflected light (white grains in graphite vein are metal, in silicate area troilite).
(Fe + Mg) ratio occur in olivines and pyroxenes of
different inclusions. Special care was taken, by
repeated measurements, to establish these differ-
ences beyond doubt. Table 3 shows the results of
repeated measurements of the same grains in two
inclusions. Table 4 gives the mean FeO contents
for olivines and FeO and CaO contents for ortho-
pyroxenes. The spread in FeO values for a given
inclusion is shown in Figure 8.
Two results are evident from Table 3 and Fig-
ure 8: (1) The spread of FeO content found within
one and the same inclusion is small, but real, as
the values are reproducible by repeated measure-
ments. (2) The difference of FeO content in olivines
in different inclusions is real and reproducible. The
clearest cases are sections 5 and 10, with an average
of 4.5 ?0.2% FeO and 3.6 ?0.2% FeO respectively.
Figure 8 shows that the ranges of FeO content in
olivine in these sections do not overlap. Most
olivine compositions of the other inclusions center
around values of 4% FeO. The pyroxene average
values are also distinctly different for different
TABLE 1.?Mineral composition of silicate inclusions 1, 4, and
5, determined by point-counting in weight percent
Mineral
Orthppyroxene . . .
Clinopyraxene ...
Plagioclase ....
Sum of silicates
Graphite
Nickel-iron . . .
Iron oxide*. . . .
Itotal
Points counted
Inclusion 1
33
35
2.5
5.4
75.9
22
0.1
0.6
1.7
100.3
1300
Inclusion 4
21
44
0.8
11.5
77.3
14
3.4
5.5
?
100.2
1000
Inclusion 5
43
21
2.7
7.8
74.5
0.8
16.5
4.9
3.2
99.9
1000
?Formed by terrestrial weathering.
NUMBER 19 111
FIGURE 7.?Graphite flakes in silicate area of inclusion 3, re-
flected light. (Width of image = 280 microns.)
inclusions, and the spread within any one inclusion
is larger than for the olivines. Compared to the
mafic minerals, the plagioclase is very constant in
composition at about 3.0% CaO, except for inclu-
sion 6 with 3.4% CaO and inclusion 8, which shows
the largest spread in An content of the feldspar
(Table 5).
The outer rim of the mafic minerals is lower in
FeO content than the central part. Table 6 gives
FeO values for several olivine centers and rims of
inclusion 8. In Figure 9 the results of microprobe
step-scans across several olivine and pyroxene grains
are plotted. The large amounts of Fe just outside
the grains are due either to a thin rim of iron oxide
(formed by terrestrial weathering) or to troilite
adjacent to the silicate grain. The drop in iron
measured at the grain boundary, despite the steep
rise just next to it, shows that this is a real effect,
since any overlapping effect of the electron beam
at the grain boundary should have raised the
iron reading, not lowered it. Mg is plotted together
with iron to show that the measured points
are still in the silicate grain. The rise in MgO
content compensating the drop in FeO (Table 6)
is not visible here, because it is too small relative
to the Mg level. In orthopyroxene Ca shows higher
values in the grain centers and lower ones towards
the rim. There is also a general tendency in the
orthopyroxene for high Fe grains to also have high
Ca contents, as shown in the CaO/FeO plot in
TABLE 2.?Composition of silicate minerals from inclusion 8, determined by electron micro-
probe (numbers in parentheses give number of grains analyzed)
Constituent
SiO2 . . .
AI2O3 ? ?
MgO . . .
FeO . . .
CaO . . .
TiO2 . .
CT2O3 ? ?
MnO . . .
Na2O . .
K2O . . .
Total
Orthopyroxene
(65)
58.9
0.25
35.2
4.37
0.79
0.20
0.37
0.39
100.4
Olivine
(63)
42.00
53.8
4.00
0.04
0.02
0.33
100.2
Diopside
(33)
55.2
0.74
17.9
1.81
21.6
0.60
1.24
0.34
0.83
100.3
Plagioclase
(53)
64.9
22.4
0.15
3.24
10.0
0.57
101.2
K-Feldspar
(2)
64.0
19.8
0.52
1.17
1.0
14.7
101.2
112 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
Inclusion 1
Section 2
32 3.6 40 44 48
Olivine
3.2 36 40 44 48 5.2 %FeO
Pyroxene
Inclusion 2
Section 3.1
3.2
5-
n
3.2 3.6 40 44
Olivine
3.6 40 44 48 5.2
Pyroxene
% FeO
15
10
?fl-r
Inclusion 2
Section 4
3.2 3.6 40 44 48
Olivine
S\
10-
3.6 40 4.4 48 5.2
Pyroxene
% FeO
u
Inclusion 2
Section 7
3.6 40 4.4
Olivine
3.6 40 4.4 48 5.2 % FeO
Pyroxene
32 3.6 40 UU
Olivine
Inclusion 2
Section 9.1
9.2
Inclusion 3
Section 1
3.6 40 l*U 48 5.2
Pyroxene
% FeO 22 3.6 40 44
Olivine
36 40 44 48 5.2 %FeO
Pyroxene
FIGURE 8.?Histograms of microprobe FeO values of different inclusions. (The suffix ".1" or ".2"
following a section number means that grains in two different areas were measured; results
from 1 are hatched except for inclusion 12.)
Figure 10. The same is true for the average Fe and
Ca contents of the orthopyroxenes in different
inclusions, higher FeO being accompanied by
higher CaO values (Figure 11).
NUMBER 19 113
Inclusion I*
Section 10.1
10.2
3.2 36 40 44
Olivine
5.2 %FeO
Pyroxene
Inclusion 6
Section 6.1
6.2
32 3.6 40 44 4.8
Olivine
36 40 44 4B 52
Pyroxene
% FeO
Inclusion 11
I Sect ion 11
_L
32 36 40 44 48
Olivine
32 3.6 40 kU 48 5.2 % FeO
Pyroxene
Inclusion 5
Section 5152
32 36 40 4.4 48
Olivine
3.6 40 44 48 5.2
Pyroxene
% FeO
Inclusion 8
Section 8.1
8.2
3.2 36 4.0 4.4 4.8 52
Olivine
36 4.0 4.4 4.8 5.2 % FeO
Pyroxene
flInclusion 12Section 12.1
32 3A 4.0 4.4 4.8
Olivine
32 3.6 40 4.4 4.8 52
Pyroxene
% FeO
Inclusion 12
Section 12.2
L
32 3.6 4.0 UU 4.8
Olivine
3.6 40 4.4 4.8 5.2
Pyroxene
% FeO
114 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 3.?FeO content of olivine grains in two thin sections
as measured on two different days by electron microprobe
Grain
No.
18
23
25
89
95
80
Mean
SECTION 1
Day 1 Day 2
4.48 4.39
4.07 4.10
4.24 4.30
4.04 4.00
4.31 4.30
4.39 4.39
4.26 4.25
Grain
No.
34
36
37
40
41
45
56
62
59
71
Mean
SECTION 10
Day 1 Day 2
3.39 3.31
3.60 3.77
3.79 3.49
3.61 3.57
3.72 3.58
3.86 3.73
3.57 3.36
3.40 3.38
2.98 2.99
3.83 3.73
3.56 3.49
Chemical Composition
Samples of three silicate inclusions, weighing 3.5
(no. 1), 6.7 (no. 2), and 9 (no. 3) grams, respectively,
were taken for chemical analysis. Number 1 was a
surface inclusion, and the location of the other two
is shown in Figure 3. These samples contained
varying amounts of metal as grains dispersed
throughout the silicate matrix and veinlets or pro-
trusions extending from the main mass of meteorite
into the silicates. Each sample was ground in a
tungsten carbide mill and passed through a 100-
mesh sieve to separate coarse metallic particles
from finely ground silicates. Since for this study
analyses of the silicates are of prime interest, only
the fraction less than 100 mesh was used for
analysis. The bulk chemical analysis was performed
in a manner similar to that described earlier
(Jarosewich, 1966). The results are shown in Table
TABLE 4.?Average FeO content of olivine and FeO and CaO content (weight percent) of
orthopyroxene of all thin sections studied
Inclusio
2
2
2:
2 :
1 :
3 :
4 :
5 :
6 :
8 :
11 :
12.
12.
n: Section"1"
3.1
3.2
4
9.1
9.2
7
2
1
10.1
10.2
5.1
5.2
6.1
6.2
8.1
8.2
11
1*12.1
2*12.2
22
24
47
21
23
14
40
25
17
26
26
31
11
38
24
39
16
32
30
Olivine
FeO
3.88 ?
3.84 ?
3.75 ?
3.87 ?
3.88 ?
3.98 ?
4.06 ?
4.16 ?
3.54 ?
3.60 ?
4.46 ?
4.62 +
3.57 ?
3.56 ?
3.99 +
4.00 ?
3.63 ?
4.03 ?
3.66 ?
A
0.10
0.19
0.26
0.21
0.19
0.15
0.25
0.14
0.19
0.17
0.19
0.17
0.25
0.28
0.15
0.26
0.17
0.25
0.26
n
29
51
96
26
25
32
29
40
34
37
14
27
35
57
39
26
27
40
33
Or thopyroxene
FeO
4.34
4.29
4.51
4.42
4.51
4.24
4.00
4.54 :
4.24 d
4.26 d
3.98 i
4.11 d
4.60 d
4.70 =
4.32 i
4.16 i
3.85 i
4.40 i
4.28 d
A
t 0.25
t 0.36
t 0.31
t 0.19
t 0.30
t 0.35
t 0.36
t 0.42
t 0.33
b 0.40
t 0.30
t 0.16
0.23
t 0.32
^ 0.26
0.29
0.23
0.39
0.26
CaO
0.76 ?
0.77 ?
0.85
0.80 ?
0.82 ?
0.74 ?
0.78 ?
0.90 ?
0.76 ?
0.82 ?
0.69 ?
0.72 ?
0.86 ?
0.94 ?
0.79 ?
0.75 ?
0.73 ?
0.84 ?
0.78 ?
A
0.07
0.09
-
0.06
0.09
0.10
0.11
0.15
0.14
0.15
0.09
0.08
0.10
0.17
0.07
0.16
0.07
0.13
0.09
Fa
3.8
3.7
3.8
4.0
4.0
4.1
3.5
4.5
3.5
4.0
3.6
4.0
3.6
Fs
6.0
6.3
6.2
5.9
5.6
6.4
5.9
5.7
6.6
5.9
5.4
6.2
6.0
Fa/Fs
0.63
0.58
0.61
0.68
0.71
0.64
0.59
0.79
0.53
0.68
0.67
0.64
0.60
The suffix .1 or .2 following a thin section number means that two different areas in the same section
were probed.
n = number of grains analyzed
A = values giving the standard deviation calculated from the distribution of the ? measurements, not
from counting statistics.
Fa = fayalite Fe~SiO,, mole percent
Fs = ferrosilite FeSiO,, mole percent
*Inclusions 12.1 and 12.2 are two different pieces on section 12.
NUMBER 19 115
TABLE 5.?Average CaO, Na2O, and K2O content of plagioclase in different inclusions
as measured by electron microprobe
Inclusion:
2:
2:
2:
2:
1:
3:
4:
5:
6:
8:
11:
12.1*:
12.1*:
Average
Section'
3.1
3.2
4
7
9.1
9.2
2
1
10.1
10.2
5.1
5.2
6.1
6.2
8.1
8.2
11
12.1
12.2
n
14
14
56
13
12
19
13
17
15
17
9
18
20
22
15
38
13
11
11
CaO
2.93 -
2.95 :
3.05 :
3.00 :
2.91 "
2.92 \
2.97 -
3.18 :
2.94 :
2.96 -
3.00 '-
3.00 :
3.50 :
3.36 :
3.12 -
3.29 :
2.91 :
2.99 H
3.16 H
A
H 0.06
I- 0.08
\- 0.15
f 0.08
f 0.06
f 0.07
? 0.09
t- 0.10
t- 0.09
t- 0.08
i- 0.06
h 0.08
h 0.31
i- 0.26
H 0.11
t- 0.45
h 0.13
h 0.09
h 0.16
Na2O
10.0
10.4 ?
11.1
10.0
10.1
10.3
10.1
9.8
10.3
10.0
10.2
9.8
8.5
9.9
10.0
10.0
10.0
9.9
9.8
K2O
0.57
0.57
0.56
0.58
0.55
0.54
0.57
0.53
0.59
0.58
0.56
0.57
0.51
0.51
0.58
0.57
0.57
0.57
0.60
A
+ 0.06
+ 0.05
+ 0.06
+ 0.04
+ 0.07
+ 0.06
+ 0.07
+ 0.05
+ 0.06
+ 0.06
+ 0.07
+ 0.06
+ 0.06
+ 0.05
+ 0.05
+ 0.07
+ 0.06
+ 0.08
+ 0.09
An
14.4
15.0
14.7
14.3
14.5
15.6
14.5
14.7
16.8
15.9
14.3
14.7
15.5
15.0
Ab
82.7
82.2
82.4
83.0
82.6
81.7
82.6
82.5
80.6
81.2
82.8
82.5
81.5
82.2
Or
2.9
2.8
2.9
2.7
2.9
2.7
2.9
2.8
2.6
2.9
2.9
2.9
3.0
2.85
+The suffix .1 or .2 following a thin section number means that two different areas in thesame section were probed.
n = number of grains analyzed.A = values giving the standard deviation calculated from the distribution of the n measure-
ments', not from counting statistics.An, Ab, Or = mole percent anorthite, albite, and orthoclase, respectively. For the calcu-
lation of these values only the CaO and K?0 measurements were used, because evaporation of Naunder the electron beam makes the Na figures less reliable.
?Inclusions 12.1 and 12.2 are two different pieces on section 12.
7. Because the carbon, troilite, and metal content
of these inclusions varies, the analyses were recalcu-
lated on a carbon, troilite, and metal-free basis in
Table 8 and compared with bulk analyses of other
silicates from iron meteorites and with chondrites.
The chondrite values for Tables 7 and 8 were cal-
culated from an average of 19 H- and 27 L-group
chondrite analyses by one of us (Jarosewich). Only
meteorites showing no signs of alteration by
weathering were chosen for the calculation of the
averages.
Discussion
COMPARISON TO CHONDRITES
Mason (1967) first noted that the minerals of the
silicate inclusions in iron meteorites are essentially
those of chondrites: olivine, orthopyroxene, diop-
side, and an albitic plagioclase. This distinguishes
them clearly from achondrites and mesosiderite
silicates, which contain anorthitic plagioclase. The
main difference from normal chondrites is the FeO
content of olivine and pyroxene, which is inter-
mediate between enstatite and bronzite chondrites
(Table 2).
The bulk chemical composition of whole inclu-
sions does not match that of chondrites. As the
amounts of metal, troilite, and graphite are highly
variable (Table 1), only the bulk compositions
of the silicates are compared here. Some of the
metal and troilite and most of the graphite are
probably secondary in origin, i.e., they were intro-
duced later into the silicate fragments.
Table 8 gives the bulk chemical composition of
the chemically analyzed inclusions 1, 2, and 3,
recalculated for the silicate portion only. Included
in Table 8 are calculated bulk chemical values for
inclusion 1 and for the additional inclusions 4 and
5. These values were calculated from the modal
composition of these inclusions (Table 1) and the
chemical composition of the minerals as determined
by the electron microprobe. The agreement between
the chemical analysis and that calculated from the
modal composition of inclusion 1 shows that these
two samples from the same inclusion are similar.
116 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
10
FIGURE 9.?Microprobe step-scan for Fe and Mg across an
orthopyroxene grain in section 8. Grain center at left, bound-
ary towards feldspar at right. Fe increase between the grains
is caused by thin vein of iron oxide formed by terrestrial
weathering.
%CaO
0.9 +
0.8-
0.7-
%FeO
40 45 50
FIGURE 11.?CaO vs FeO, average values of orthopyroxenes
from different sections.
This is an important test to determine whether or
not the chemical differences between different
inclusions, as shown in the values of Table 8, are
due to sample inhomogeneities or are real. These
variations are already evident from the variations
in modal composition of inclusions 4 and 5 (Table
1). In Table 8 an average composition for the
inclusions 1 to 5 has been calculated, although it
seems doubtful that such an average gives mean-
ingful values.
A consistent feature of the inclusions is the lower
FeO-content compared to chondrites, which is
caused by the lower FeO-content of the mafic min-
erals. In Table 9, therefore, the silicate composition
1.5+
1.0-
0.5-?
%CaO
6.1 ?
6.2 o
4.0 5.0 % FeO
FIGURE 10.?CaO vs FeO in orthopyroxene from inclusion 6.
TABLE 6.?FeO content (weight percent) of olivines
in inclusion 8
Grain Ifo.
38
43
44
45
51
55
79
81
Mean
Center
4.18
3.83
4.09
4.28
4.35
4.39
4.39
4.34
4.23
Rim
3.71
3.45
3.80
3.79
3.98
3.62
3.91
4.00
3.78
NUMBER 19 117
TABLE 7.?Chemical composition of three El Taco silicate inclusions and average of 19 H-
and 26 L-type chondrites (some unpublished results are included in averages; analyst:
E. Jarosewich)
Constituent
Fe . . . .
Ni . . . .
Co ....
FeS ...
SiO2 . . .
TiO2 . . .
AI2O3 . .
CT2O3 . .
FeO . . .
MnO . . .
MgO . . .
CaO . . .
Na2? ? ? ?
K2O ...
P2?5 ? ' ?
H2Of . . .
H2O- . . .
C . ...
Total
Total Fe
No.l
Surface
1.75
0.18
0.02
0.33
37.82
0.13
1.36
0.10
3.95
0.35
28.63
1.09
0.52
0.04
0.39
1.13
0.07
23.00
100.86
5.03
Location
No.2
11B-25/2-5
0.80
0.27
0.02
7.29
45.86
0.12
3.41
0.33
4.94
0.32
28.27
1.09
1.23
0.11
0.26
0.85
0.17
5.35
100.69
9.27
No. 3
11B-24/19-22
0.25
0.10
<0.01
1.32
40.52
0.13
1.64
0.30
3.33
0.31
31.94
2.48
0.47
0.06
0.03
0.76
0.12
16.41
100.17
3.68
Chondrite
H-type L-type
15.71
1.72
0.09
5.56
36.41
0.12
2.11
0.52
10.54
0.31
23.23
1.74
a 84
0.09
0.27
0.46
0.13
0.12
99.97
27.49
6.47
1.25
0.06
6.00
39.81
0.13
2.20
0.52
14.68
0.33
24.69
1.87
0.96
0.11
0.22
a 53
0.14
0.19
100.16
21.69
has been recalculated without FeO, to give a better
comparison to chondrites. The variations between
different inclusions and the deviations from the
chondritic average are most pronounced for the
elements Al, Cr, Ca, Na, K, and P. Also the mean
MgO content is higher, although the values of
inclusions 2 and 4 are close to the chondrite aver-
age. The chemical variability and the deviations
from chondritic values are also shown by the ele-
ment ratios included in Table 9. The mean Mg/Si
atom ratio (X 100) of 110 is higher than in normal
chondrites (94), and closer to the value for carbon-
aceous chondrites of 104 (Ahrens and von Michaelis,
1968); on the other hand the Ca/Si ratio of 3.5 is
lower than the chondritic average of 5.0 and more
similar to the ratio of enstatite chondrites, which is
3.0 (Ahrens and von Michaelis, 1968). These agree-
ments seem to be fortuitous, however, in view of
the large variations between the inclusions. It is
also evident from Table 9 that inclusions which
show agreement in one of the element ratios with
the chondritic value do not do so in other ratios.
The best illustration of the chemical variations is
given by the Ca/Al ratio. It varies here by a factor
of 5 between 28 and 140, whereas this ratio is very
constant at 74 ?6 (atom %) for all stony meteorite
groups including the achondrites (Ahrens and von
Michaelis, 1969).
118 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
TABLE 8.?Composition of the silicate portion of inclusions 1-5, compared to chondrites
and mesosiderites
Constituent
Si02
TiO2
A12?3
Cr2?3
FeO ,
MnO
MgO
CaO
Na2O
K20
P2?5
Chemical analysis
2 3 1
Calculated from
the Mode
14 5
Average of
inclusions
1-5
Average silicate portion
Chondrites* Mesosi-
H-group L-group derites'*'
53.4
0.14
3.97
0.38
5.75
0.37
32.9
1.27
1.43
0.13
0.30
49.9
0.16
2.02
0.37
4.10
0.38
39.3
3.05
0.58
0.07
0.04
50.8
0.17
1.83
0.13
5.31
0.47
38.5
1.47
0.70
0.05
0.52
50.4
0.11
1.8
0.17
3.6*
0.34
41.4
1.3
0.7
0.03
n.d.
54.1
0.12
3.7
0.18
3.4
0.34
35.5
1.1
1.4
0.04
n.d.
48.0
0.08
2.5
0.13
3.8
0.32
42.4
1.35
1.0
0.03
n.d.
51.2
0.13
2.80
0.24
4.5
0.38
37.7
1.65
1.0
0.08
0.29
47.8
0.16
2.77
0.68
13.84
0.41
30.5
2.28
1.10
0.12
0.35
46.5
0.15
2.59
0.61
17.17
0.39
28.9
2.18
1.12
0.13
0.26
52.9
0.47
8.74
n.d.
13.51
0.51
14.86
5.67
n.d.
0.01
0.83
The chemical analyses are from the data of Table 7, recalculated on a metal-, troilite-, carbon-, and
water-free basis. Inclusions 1, 4, and 5 were calculated from the modal composition values of Table 1
and the chemical composition of their minerals determined by electron microprobe.
*from Table 7
+from B.N. Powell (1971)
xThis value gives FeO in the silicates only, not FeO due to weathering (Table 1).
n.d. = not determined
TABLE 9.?Composition of silicate inclusions 1-5 and chondrite average from Table 8, recal-
culated also without FeO (element ratios are calculated from atom percentages)
Constituent
Si02 ,
TiO2 ,
Al203
Cr203
MnO
MgO
CaO
Na20
K20
P2O5
TOO Al/Si ..
100 Mg/Si ..
100 Ca/Si ..
100 Ca/Al ..
Chemical Analysis
2 3 1
Calculated from the Mode
1 4 5
Average of
inclusions
1-5
H- and L-
Chondrites
Average *
56.60
0.15
4.21
0.41
0.40
34.90
1.35
1.52
0.14
0.32
29.00
52.00
0.17
2.10
0.38
0.40
41.00
3.18
0.60
0.08
0.04
140.00
53.70
0.18
1.93
0.14
0.50
40.70
1.55
0.74
0.06
0.55
8.80 4.80 4.20
92.00 117.00 113.00
2.60 6.50 3.10
73.00
52.30
2.00
42.90
1.35
0.75
0.03
4.50
122.00
2.80
62.00
56.00
36.70
1.15
1.50
0.04
28.00
50.00
2.65
44.10
1.40
1.10
0.03
8.00 6.20
98.00 131.00
2.20 3.00
48.00
53.70
0.17
2.94
0.31
0.43
39.50
1.73
1.10
0.10
0.30
6.50
110.00
3.50
53.00
55.80
0.18
3.17
0.76
0.47
35.10
2.63
1.32
0.15
0.36
6.70
94.00
5.00
75.00
* H- and L-chondrite compositions are so similar on this basis that the average of both groups was taken.
NUMBER 19 119
FIGURE 12.?Border zone of silicate inclusion 3, transmitted
light. Coarse silicate grains occur next to the graphite zone
(black, top) at the metal to silicate inclusion boundary,
smaller silicate grains with graphite flakes (black) further in-
side (bottom). (Width of image = 1.5 mm.)
As Ca and Al are located in diopside and feld-
spar in these inclusions, we tried to match the
composition of chondrites more closely by the
addition or subtraction of one or both of these
minerals. A fit for Ca and Al should also result
in correct values for Na and K, as these elements
are found in feldspar only. Because the composi-
tion of the minerals in these inclusions is so close
to that of chondrites, it is self-evident that a mix-
ture of these minerals in the right proportions
should also produce a good match to the bulk
chemistry of chondrites. Nevertheless, it is inter-
esting to see how much diopside or feldspar of the
analyzed composition has to be added or subtracted
to come close to a chondritic silicate composition.
For this comparison FeO has again been omitted
from the calculations, as its content is much lower
in El Taco olivines and pyroxenes than in ordinary
chondrites. The results are shown in Figure 13:
chondritic compositions can be matched quite well
by addition or subtraction of small amounts of
diopside and/or plagioclase for all inclusions. The
correction is not sufficient, however, to match the
Mg/Si ratio of normal chondrites completely. To
achieve this, also the pyroxene/olivine ratio has to
be increased: a ratio of 2:1 as in inclusion 4 would
be appropriate.
Thus it seems feasible to derive these inclusions
from chondritic material (neglecting the FeO con-
tent, which is discussed further below), from which
mainly feldspar and/or diopside was lost (the
grains in inclusion 2 and 3 are so small that they
may be neglected). A mechanism for this derivation
would be partial melting and redistribution of the
melt, as albite and diopside would be the first
minerals to melt, at 1120? and 1390? C, respectively.
It is important to note, however, that different
inclusions need different amounts of diopside and
feldspar and that these minerals are not lost in
proportional amounts, as already evident from the
highly variable Ca/Al ratio of these inclusions. It
can be seen from the values of Table 1 that the
relative amounts of olivine and pyroxene also vary
by a factor of 2. These variations are probably not
due to sampling errors, as the good agreement of
chemical and calculated analysis of different areas
of inclusion 1 (Table 8) shows. It may be argued,
however, whether the lower melting silicates were
entirely lost from the inclusion or may still be
present in a small border zone towards the metal.
A simple calculation shows that a surface layer 0.5
mm thick of an inclusion (Figure 12) with the
dimensions 3x3x6 cm (like inclusion 3) would
contain 8% of the material of this inclusion by
volume. This border zone would then have to
consist entirely of feldspar and/or diopside to
account for the material which was lost (Figure
13). This is not observed in thin sections that are
available from the metal-silicate interface of inclu-
sions 2 and 3. Feldspar is somewhat enriched in
this zone but it is still a minor phase in relation
to pyroxene and olivine. Thus, it seems safe to
conclude that the variations in chemical and min-
eralogical composition of these inclusions are due
neither to inhomogeneities nor to nonrepresenta-
tive sampling.
120 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
2.0-
1.5-
1.0
0.8:
0.6:
0.4-
0.2-
0.1 ISi Mg Al Co No K Cr
Q+5% diopside and +7% feldspar
Inclusion 1
2.0-
1.5-
1.0:0.8-
O.fr
0.4-
0.2-
0.1-
NWWWWW1 71
/ 7
-
Si Mg Al Ca Na K Cr
+7% diopside and -2% feldspar
Inclusion 2
2.0-
1.5-
1.0:
0.8-
0.6-
0M-
0.2-
0.1:
Si Mg Al Ca Na K Cr
-3% diopside and +8% feldspar
Inclusion 3
zo-
1.5-
1.0
0.8-
0.6-
0.4-
0.2-
0.1- Si Mg Al Ca Na K
+ 8% diopside and -2% feldspar
Inclusion U
2.0
1.5
1.0
0.8
0.6
0.4-
0.2-
0.1
-
7\
/
/ r-
/
/ 171
Si Mg Al Ca Na K
+7% diopside and+3% feldspar
Inclusion 5
FIGURE 13.?Open bars: Main element content of
silicate portions of inclusions 1 to 5, normalized to
average chondrite composition (from Table 9).
Hatched bars: Composition after addition or sub-
traction of the indicated amounts of diopside and
plagioclase feldspar of the composition measured
in inclusions 1-5.
NUMBER 19 121
The match with chondrites for the main elements
extends also to the minor ones, such as Ti and Mn.
Notable exceptions, however, are Cr and P, which
are highly variable, and K, which is usually too low.
In chondrites, Cr is mainly contained in
chromite. If FeO is reduced to iron metal, the next
element to be reduced would be Cr, according to its
redox potential. If chromite is consumed by reduc-
tion, first Fe is reduced, so that the residual chro-
mite should become very high in Cr. This is found
in the El Taco chromites (Bunch, Keil, and Olsen,
1970, table 7). Upon further reduction, Cr also
leaves this mineral and enters troilite. The troilite
of the El Taco inclusions contains 0.3% Cr (Bunch,
Keil, and Olsen, 1970, table 8). Thus, Cr can be
lost from these inclusions in variable amounts
according to its degree of reduction and the fate of
the troilite of a specific inclusion. Inclusion 1,
which is lowest in FeS (Table 1), is also lowest in
Cr (Table 9).
In the case of P, both reduction and partial
melting may be responsible for its variations.
Apatite may be reduced to schreibersite, as their
coexistence close to one another shows. It could
also be removed or redistributed by partial melting.
In the thin sections small apatite grains are found
throughout the silicates, usually in association with
troilite grains, but larger ones occur only at the
border to the metal host or to metal /graphite
veins.
VARIATIONS IN MINERAL COMPOSITION
Besides the variations in bulk composition, slight
but distinct differences exist in mineral composi-
tion, as shown in Table 2 and Figure 8. In several
of the FeO-histograms of Figure 8 measurements
of different areas of the same inclusion are plotted.
These show that in a given inclusion the distribu-
tion of FeO values for pyroxenes and olivines and
the average are constant, but that different inclu-
sions can have differences outside the analytical
error. Also, the ratio of Fe/Mg in olivine to this
ratio in pyroxene varies, as low FeO contents in
olivine may coexist with high FeO content of
pyroxene, and vice versa.
In general, in the El Taco inclusions and in the
silicate inclusions of other IAB irons (Bunch,
Keil, and Olsen, 1970), the Fe/(Fe + Mg) atom
ratios are higher in pyroxene than in olivine,
whereas in normal chondrites and terrestrial rocks,
olivine in equilibrium with orthpyroxene is more
iron-rich (Keil and Fredriksson, 1964; Medaris,
1969). This led Olsen and Fuchs (1967) to the con-
clusion that equilibrium was not reached in these
silicate inclusions. Later, however, Olsen and
Bunch (1970) argued that equilibrium should have
been reached during the long cooling times of iron
meteorites (1? to 10? C per 106 years, according to
Goldstein and Short, 1967:1733). As they did not
find any signs of disequilibruim, such as variable
Fe contents or zoning, they concluded that an
equilibrium with a reverse trend occurs at low FeO/
(FeO + MgO) percentages, so that the pyroxene
becomes more iron-rich than the coexisting olivine.
The measurements on El Taco show that there are
clear indications of disequilibrium between differ-
ent inclusions. The most striking indication is the
variation in the ratio of Fe/Mg in olivine over
Fe/Mg in pyroxene (Table 4). The other is the
slight zoning of the FeO content in the mafic min-
erals. Table 6 and Figure 9 show that the rims of
olivine, pyroxene, and diopside grains have lower
iron contents than the central part. The crystalliza-
tion zoning should be just the opposite, as Fe-rich
olivines and pyroxenes melt at lower temperatures
than their Mg-rich counterparts.
It should be emphasized that we are speaking of
three kinds of disequilibrium: (1) disequilibrium
between different inclusions, expressed as different
Fe/Mg ratios in olivine compared to Fe/Mg in
pyroxene; (2) disequilibrium within single olivine
and pyroxene grains of one inclusion, the rim
being depleted in iron compared to the center; and
(3) "equilibrium" within one inclusion, that is a
narrow range of Fe/Mg ratios in olivines and
pyroxene. In a given inclusion, the large olivine
and pyroxene grains which are close to the metal
border usually have the highest FeO contents. On
the other hand, there is no simple relationship
between the average grain size of an inclusion and
the average FeO content of its mafic minerals.
Contrary to the observation on single grains men-
tioned above, inclusion 5 with the highest average
FeO content in the olivine has one of the smallest
grain-size textures.
The composition of the main minerals is very
close to that of chondrites except for the lower FeO
content of the mafic minerals. This implies a
slightly more reduced condition of this material,
but not nearly as reduced as that of enstatite
122 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
chondrites. Enstatite in enstatite chondrites con-
tains 0.7% FeO (type i) or 0.2% FeO (type n),
according to Keil (1968). Their more reduced state
is also reflected in the presence of 1% to 3% Si in
the kamacite metal (Ringwood, 1961: Keil, 1968).
No Si was detected in the metal of the El Taco
silicate inclusions. It has also been shown by Olsen
and Fuchs (1967) that the coexistence of schrei-
bersite and phosphates in these inclusions allows
for an oxygen fugacity during their last high-
temperature transformation of 10~20 atm, which is
in the same range as that of normal chondrites. The
minor-element content of the orthopyroxene is
close to the values for this mineral from normal
chondrites but usually higher than that of enstatite
from enstatite chondrites. (Table 2).
FELDSPAR COMPOSITION
The anorthite content of 15 mole percent is close
to that of normal chondrites, but is even closer to
the feldspar of enstatite chondrites (Table 10).
Thus the El Taco oligoclase fits into this general
sequence of increasing An content with decreasing
Fe content of olivine and pyroxene. The Or con-
tent of 3 mole percent is notably low in El Taco.
This is the reason that the addition of this feldspar
to the bulk silicate composition of the inclusions
gave a good match to chondritic values for Na, but
not for K (Figure 13). For the same reason the
analysis calculated from the mode of inclusion 1
is too low in potassium, whereas it agrees well with
the chemical analysis for sodium (Table 8). The
Na/K atomic ratio of the feldspar is 26.6, whereas
TABLE 10.?Feldspar composition (mole percentages) in El
Taco inclusions compared to the average compositions in L-,
H-, and enstatite chondrites
Sample
El Taco, range
average
L-chondrites
H-chordrites
Enstatite chandrites, type 2
Anorthite Qrthoclase
14.3-15.9
15.0
10
12
15
2.7-3.0
2.8
5
6
4
*Van Schraus and Ribbe, 1968, table 1,
fKeil, 1968, table 4
in the bulk analyses this ratio varies between 12
and 20 and is thus closer to the value of 13.5 for
the average chondrite (Table 7). This means that
an additional phase containing potassium must be
present. This was found as small K-feldspar grains,
which are only a few microns across and occur
usually at plagioclase-graphite grain boundaries.
The average composition of two grains large
enough for analysis is given in Table 2. Small K-
feldspar grains associated with albite in the
Odessa iron meteorite were reported by El Goresy
(1967). Bunch, Keil, and Olsen (1970) observed K-
enriched zones in the feldspar of Odessa and
Toluca and thought them due to K-leaching by ter-
restrial weathering. This explanation can be ex-
cluded for El Taco by the microprobe analysis of
these grains. They can be explained by exsolution
from the albitic plagioclase because of the expand-
ing solvus at low temperatures. The temperature
of exsolution of the albite according to the solvus
determined by Goldsmith and Newton (1974)
should be below 600? C and lower than the last
equilibration temperature of chondritic feldspars.
Recently, a phase containing 50 mole percent Or
was observed as exsolution lamellae in the albitic
plagioclase of a silicate nodule in the San Cristobal
iron (Scott and Bild, 1974).
CLINOPYROXENE-ORTHOPYROXENETHERMOMETRY
The Wo content of the diopsides in El Taco of
44 mole percent would correspond to a tempera-
ture of about 1000? C on the diopside solvus of
Davis and Boyd (1966). The KD value for the Fe/
Mg equilibrium between diopside and orthopy-
roxene as used by Kretz (1963) and McCallum
(1968) gives a much higher temperature. For the
pyroxenes of inclusion PTS 8 KD = (Fe/Mg) ortho-
pyroxene/(Fe/Mg) clinopyroxene gives a value of
1.11. On McCallum's equilibrium curve this would
correspond to a temperature of about 1700? C. This
temperature is much too high, and if reduction of
FeO from the silicates took place the temperature
derived in this way is probably meaningless.
ORIGIN OF THE INCLUSIONS
The similarity between chondritic and the El
Taco silicate minerals favors a close relation be-
tween the two. Whether this is a genetic one, so
NUMBER 19 123
that El Taco silicate inclusions were derived by
transformation of chondrite material, cannot be
answered with certainty. Furthermore, there are
many ways in which a chondrite could be trans-
formed to give the El Taco silicates. Three features
have to be explained: the lower FeO content of the
mafic minerals, the apparent differences in bulk
composition, and the disequilibrium between dif-
ferent inclusions.
One simple model that would explain most of the
El Taco silicate inclusion features would be the
incorporation of chondritic matter into a hot iron
metal, at or near to the nickel-iron melting point
of about 1500? C. Heating of a chondrite with H-
type olivine and pyroxene in an atmosphere of CO
and CO2 in equilibrium with one another will
lead to a reduction of iron silicates above tempera-
tures of about 1200? C. It has been shown by
Mueller (1963) and Speidel and Nafziger (1968)
that an olivine-silica-metal assemblage will change
towards lower fayalite contents in the olivine when
heated from 1100? to 1300? C. A reduction of the
silicates to about 6 mole percent FeO, which is
found in most of the silicates of iron meteorites
with silicate inclusions (Bunch, Neil, and Olsen,
1970), may then reflect the equilibrium at the tem-
perature of molten nickel-iron. At this tempera-
ture albite and diopside will melt also, but not
olivine and enstatite, a condition which could ex-
plain the depletion of the former minerals dis-
cussed above. The apparent disequilibrium between
different inclusions was probably not established at
these high temperatures, but later during cooling,
and may be the last change produced by a contin-
uing reduction of iron oxide from the silicates. The
lower FeO mole percent of olivine may then sim-
ply reflect the fact that olivine is easier to reduce
than pyroxene. That this is the case was shown
in the ureilite Havero, where olivine next to
carbon-rich veins is reduced to lower FeO contents,
whereas pyroxene is not (Wlotzka, 1972).
The question remains, why did the high-
temperature reduced assemblage not change back to
its original, more oxidized form upon slow cool-
ing? This difficulty can be overcome by changing
from a closed to an open system, which would be
the result in a change from rapid heating to slow
cooling. A rapid heating process, as by an intro-
duction of silicates into a molten metal pool or
invasion of a chondritic rock by a metal melt,
would essentially result in a closed system with re-
spect to C/CO/CO2 because the time for escape
of the gases was too short. Thus the equilibrium
between CO and CO2 would establish the low Fa
and Fs content of the mafic minerals at this high
temperature. Slow cooling, which took place during
the y-a transformation between 850? and 600? C
over some 100 million years (Goldstein and Short,
1967), will result in an open system, where oxygen
removed by the reduction of Fe-silicates by carbon
may escape and provide for the continuing reduc-
tion. The differences from inclusion to inclusion can
then be explained by local differences in carbon
available per inclusion or weight-unit of silicates.
These differences are mainly due to a different FeO
content of the olivines, since the pyroxene com-
positions are more uniform. As olivine is more
easily reduced than pyroxene, its composition will
follow these changes better than that of pyroxene.
Thus the low FeO content of olivines from the
small, veinlike inclusion 6 may be caused by the
higher amounts of carbon available from the metal
in this area.
The proportionality of Fe and Ca in orthopyrox-
ene (Figure 10) is not in contradiction to a loss of
FeO by reduction. Both FeO and CaO will be
leaving the pyroxene grains by diffusion?FeO be-
cause it is reduced to Fe metal, and CaO because
at lower temperatures the solubility of CaSiO3 in
the enstatite is lowered (Davis and Boyd, 1966).
Another possibility is a genetic relationship of
the material of the El Taco inclusions to chondrites
like Kakangari (Graham and Hutchison, 1974),
which already contain olivines with a low fayalite
and pyroxene with a low ferrosilite content, so that
a reduction is not necessary. Only the late reduc-
tion leading to the disequilibrium between olivine
and pyroxene and between different inclusions
has to be operative here too.
Summary and Conclusions
It has been shown that (1) the silicate minerals
of the El Taco inclusions have a composition close
to the minerals of chondrites with the exception
of a lower iron content of olivine and pyroxene;
(2) the iron content of olivine and pyroxene shows
small but distinct variations from inclusion to in-
clusion; and (3) the bulk chemical composition is
124 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES
close to chondrites with deviations mainly in the
alkalies, Ca, and Al.
We suggest an explanation of these features by
an in-situ reduction of chondritic material at the
temperatures of molten nickel-iron together with
partial melting and redistribution of the more
fusible minerals, feldspar and diopside. The vary-
ing Fe/Mg ratios of olivine and pyroxene in dif-
ferent inclusions are explained as a minor dis-
equilibrium due to continuing reduction at lower
temperatures. The following observations appear
to support this explanation:
Partial melting is supported by the rare-earth
data on Woodbine by Masuda (1969) and Hinten-
berger and Berghof on El Taco (1970). The rare
earth pattern shows a depletion in Eu and other
deviations from the chondritic pattern, which can
be explained by loss of a feldspar component.
Evidence for reduction of the mafic minerals is
the FeO-depletion of the marginal zones of oli-
vines and pyroxenes. This is supported by the ob-
served reduction of Cr, which moves from chromite
into troilite. Another hint in this direction is the
lower Ni-content of the metal particles in the sili-
cate inclusions compared to the metal host, which
has been reported by Bunch, Keil, and Olsen
(1970). This could be a dilution effect caused by
the newly formed metallic iron.
Not much evidence is available for an in-situ
process. A simple relation between size or location
of the inclusions and their composition has not yet
been found, except for the fact that the small vein-
like inclusion 6 has one of the lowest and most
variable FeO-contents in its mafic minerals. More
inclusions of this type should be studied to answer
this question.
On the other hand, the variations in composition
and texture between large inclusions, together
with a homogeneous composition of individual in-
clusions, are easier to understand if the differen-
tiations took place before incorporation into the
metal host. In any case, however, these differentia-
tions are small compared to the differentiations
which separate achondrites or mesosiderites from
chondritic material. These inclusions are still close
to primitive material and not what one would
expect at the boundary between iron core and
mantle of a planetary body. The "raisin-bread"
theory, which sees the iron meteorites formed in
small pools dispersed through silicates (Urey, 1959),
fits the observations on El Taco better. It does not
seem possible, however, to go one step further, as
Wasson (1970) does, and assume that group I irons
and their silicate inclusions are primitive conden-
sates and were never molten. These inclusions vary
in bulk and mineral composition, which means
they were either formed under different conditions
in different regions (if one wants to retain their
primitive nature) or they were differentiated by
melting processes. The latter seems much more
probable.
Literature Cited
Ahrens, L. H., and H. von Michaelis
1968. Fractionation of Some Abundant Lithophile Ele-
ment Ratios in Chondrites. Pages 257-272 in L. H.
Ahrens, Origin and Distribution of the Elements.
Oxford: Pergamon Press.
1969. The Composition of Stony Meteorites, III: Some
Inter-Element Relationships. Earth and Planetary
Science Letters, 5:395-403.
Bence, A. E., and A. L. Albee
1968. Empirical Correction Factors for the Electron Micro-
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