Contributions to Modern and Ancient Tidal Sedimentology: Proceedings of the Tidalites 2012 Conference, 
First Edition. Edited by Bernadette Tessier and Jean‐Yves Reynaud. 
© 2016 International Association of Sedimentologists. Published 2016 by John Wiley & Sons, Ltd. 217
Cataclysmic burial of Pennsylvanian Period coal swamps  
in the Illinois Basin: Hypertidal sedimentation during  
Gondwanan glacial melt‐water pulses
ALLEN W. ARCHER*†,  SCOTT ELRICK‡,  W.  JOHN NELSON‡ and  
WILLIAM A. DIMICHELE§
† Department of Geology, Kansas State University, Manhattan, Kansas, 66506, USA
‡ Illinois State Geological Survey, Champaign, Illinois, 61820, USA
§ Department of Paleobiology, NMNH, Smithsonian Institution, Washington, D.C., 20560, USA
* E‐mail: aarcher@k‐state.edu
INTRODUCTION
Objectives and study area
The objectives of this research include the docu­
mentation of the common occurrence of upright 
plants within shale‐rich lithofacies that directly 
overly coals. From a sedimentological perspec­
tive, very rapid generation of accommodation 
space would apparently be required to preserve 
rapid plants. Lacking clearly defined modern ana­
logues, the authors suggest that the deglaciations 
and meltwater surges during the Late Cenozoic 
Era (Pleistocene and Neogene Epochs) might 
 contain meaningful ‘modern’ analogues.
Pennsylvanian Period coal forests, in terms of 
taxonomic composition, diversity and long‐term 
dynamics, lack clearly‐defined modern counter­
parts (Falcon‐Lang & DiMichele, 2010). These pal­
aeoforests were unique in the history of the Earth’s 
terrestrial vegetation and were amongst the most 
globally extensive terrestrial ecosystems in Earth 
history (DiMichele et al., 2001).
ABSTRACT
Roof facies of widespread, Pennsylvanian Period, economically important coals in the 
Eastern Interior Coal Basin (Illinois Basin) commonly exhibit evidence of extensive 
and cataclysmic tidal sedimentation during rapid marine‐flooding events. Upright 
Trees and smaller plants were covered and entombed by swiftly deposited, thin‐bedded 
and laminated mud and sand. This facies has historically been interpreted as fluvial‐
style cross bedding. Detailed examination clearly shows that these facies consist of 
inclined heterolith stratifications (IHS). Entire forests of upright trunks have been 
 documented in the roof strata of surface and underground coal mines. Detailed sedi­
mentological analyses of mine‐roof facies indicate a pervasive and significant tidal 
influence. In some cases, daily and semi‐monthly tidal periods have been preserved 
within laminated facies (‘tidal rhythmites’). Based upon modern analogues, the tidal 
facies are indicative of hypertidal conditions. The hyper‐dynamic tidal regime resulted 
in rapid sediment accumulation, particularly along pre‐existing drainages within the 
ancient coastal swamp. Stratigraphic successions indicate a recurring pattern of very 
rapid change from widespread coal‐swamp conditions to tidally‐influenced deposi­
tion. The repetition of these stratigraphic phenomena throughout the Pennsylvanian 
Period suggests significant external controls on sea‐level, probably related to Gondwanan 
deglaciations and resultant large‐scale meltwater pulses. Despite the rapid changes of 
sea‐level rise, the hypertidal depositional dynamics resulted in conditions whereby 
inundated coastal forests were buried by tidally influenced sedimentation.
Keywords: Pennsylvanian, coal swamps, hypertidal sedimentation, Illinois Basin, 
Gondwana glaciations, melt‐water pulses, Holocene.
218 A. W. Archer et al.
Extensive coal‐mining activity in the U.S. and 
Europe has resulted in numerous exposures for 
study and analysis. Within the Illinois Basin area of 
the east‐central U.S. (Fig. 1) mining of bituminous 
coal began circa 1820 and became an important 
industry by 1880. Today, it remains a key compo­
nent of electrical‐power generation worldwide. 
Due to the economic incentive to core‐drill and 
excavate Pennsylvanian coal‐bearing strata, we 
may know more about these terrestrial ecosystems 
than any others in Earth history. However, there 
remain many enigmas, such as upright palaeofor­
ests, that have yet to be completely explained.
‘Cyclothem’ models
Pennsylvanian coal measures in the U.S. midcon­
tinent contain lithostratigraphic units that in most 
cases have a very high degree of vertical repetition 
and lateral continuity. More precisely, many thin 
Pennsylvanian beds of underclay (palaeosols), 
coal, black‐sheety shale and limestone exhibit 
great lateral persistence throughout and between 
major basins, such as the Appalachian Basin to 
the east and Forest City Basin to the west (Wanless & 
Weller, 1932; Archer & Greb 2011).
A generalised model of cyclical sedimentation, 
the ‘cyclothem,’ was initially developed in Illinois 
Basin (Weller, 1930, 1931) and subsequently applied 
to other areas, particularly in Kansas (Moore, 1935, 
1964). Despite the seeming elegance of the cyclo­
them model, the concept has never been statisti­
cally or numerically verifiable (Zeller, 1964; 
Wilkinson, et al., 2003). The model was used to 
define formations in Illinois during the 1940s and 
1950s. Today, neither the Illinois nor the Kansas 
geological surveys retain the cyclothem concept as 
a part of formal lithostratigraphic nomenclature. 
100°W 
90°W 80° W 
70° W 
50°N
40°N
30°N
Jenlin
Creek Paum
New Futures Ab
Ib
Bb
Fb
Fig.  1. Location of major Pennsylvanian coal basins in the eastern U.S. including the Appalachian Basin (Ab), Black 
Warrior Basin (Bb), Illinois Basin (Ib) and Forest City Basin (Fb). Specific sites within the Illinois Basin refer to active 
mines where upright trees are particularly common, well preserved and studied for this report.
Cataclysmic burial of Pennsylvanian Period coal swamps in the Illinois Basin 219
As  there are difficulties in defining and mapping 
 ‘cyclothems,’ the concept should only be used 
informally (Kosanke et al., 1960; Archer, 2008).
Coals
The stratigraphic succession encompassing the 
major economic coals of the Illinois Basin is the 
Desmoinesian Series of the Pennsylvanian System 
(Fig. 2). The Desmoinesian corresponds to the upper 
Moscovian and lower Kasimovian stages in the 
international time scale (Granstein et al., 2012). 
Although coal beds ranging from Chesterian through 
Virgilian age have been mined in the Illinois basin, 
over 95% of resources and historic mining lie 
within the Desmoinesian Series. Within the Illinois 
Basin the major coals are of moderate thickness 
(typically 1 to 3 metres) but are regionally extremely 
extensive. Many coal beds can be traced with cer­
tainty from the Illinois basin into the Forest City 
basin (easternmost Kansas and environs) and prob­
ably into the northern Appalachian basin. In 
 particular, the Herrin and Springfield coals are 
 particularly widespread (Greb et al., 2003).
Siliciclastic units
There two basic types of shale that directly over­
lie coal beds. This includes very black shale or 
shale that exhibits lighter‐coloured shades of 
grey. The black, highly fissile phosphatic shale is 
commonly associated with thin limestone beds 
and both of these lithofacies can be very laterally 
continuous. This type of shale has been infor­
mally described as ‘slate‐like’ or ‘sheety’ because 
it readily breaks into thin lamina and beds. 
Overall thicknesses of these units are rarely 
greater than 2 m and vertebrate and invertebrate 
faunas indicate widespread marine influences 
(Zangerl & Richardson, 1963). Some common fos­
sils include the scallop Dunbarella, the inarticu­
late brachiopods Lingula and Orbiculoidea, 
occasional nautiloids and also fish remains, par­
ticularly sharks. Abundant conodonts provide a 
useful biostratigraphic framework. Within the 
subsurface, elevated amounts of radioactive ele­
ments yield a strong gamma‐log response in the 
geophysical logs of black shale. Thus, the black 
shales are important for regional biostratigraphic 
and lithostratigraphic correlations. Many black 
shale units are so confidently correlated (e.g. 
Anna, Excello) that they carry the same name 
throughout the Illinois and Forest City basins.
At the other end of the shale spectrum, gray‐shale 
units also include siltstone and sandstone. This 
lithofacies has been termed a ‘gray shale wedge’ 
(GSW) and, as compared to black shale, exhibits a 
much higher degree of lateral and vertical variability 
(Wanless, 1964). GSW facies are thickest adjacent to 
major river drainages that were contemporaneous 
with the widespread peat swamps (Hopkins, 1968; 
Gluskoter & Hopkins, 1970; Allgaier & Hopkins, 
Danville 
Springfield
Houchin Creek
Colchester 
Seelyville
Herrin
D
E
S
M
O
IN
E
S
IA
N
0
10
20
30
40
50
60
C
ar
bo
nd
al
e
S
he
lb
ur
n
Tw
M
etres
Fig.  2. Stratigraphic diagram showing positions of major 
coals and associated grey‐shale wedges (tongue‐like chan­
nels). Scale in metres.
220 A. W. Archer et al.
1975). GSWs are the most important factor in coal 
quality and thickness. Thicker coal seams, overlain 
by more than 6 m‐thick GSW, are lower in sulphur 
(1 to 2%) when compared to the usual levels of sul­
phur (3 to 5%) that occur in coal beds overlain 
directly by black shale. This pattern has been docu­
mented within several coal seams but most thor­
oughly for the Colchester, Springfield and Herbrin 
Coals (Hopkins 1968; Gluskoter & Simon, 1968, 
Gluskoter & Hopkins, 1970; Allgaier & Hopkins, 
1975; Kvale & Archer, 1990).
Sequence stratigraphy
A prominent regional unconformity separates the 
older Mississippian System from the overlying 
Pennsylvanian strata in the Illinois Basin. A sub‐
Pennsylvanian unconformity is present in most 
places across the North American craton (Bristol & 
Howard, 1971, 1974).
GSW and the associated lateral lithostratigraphic 
variability were initially interpreted as the product 
of a terrestrial environment of deposition. This was 
related to the lack of obvious marine fossils and 
the common occurrence of well‐preserved plant 
 fossils. The progressive development of incised, 
 valley‐fill (IVF) models as well as tidal‐estuarine 
models in the 1980s provided an alternative depo­
sitional model (Dalrymple et al., 1991, 1994, 2012; 
Archer & Kvale, 1993; Archer et al., 1994; Archer & 
Feldman, 1995; Nelson et al., 2002).
IVF models helped to explain the localised dep­
osition within sub‐Pennsylvanian valleys first 
noted by Bristol & Howard (1974) and also served 
to explain the GSWs initially described by Wanless 
(1964). Owing to concurrent palaeoglacial‐eustatic 
flux, IVFs appear to be particularly common in 
the late Palaeozoic (Falcon‐Lang, 2004; Falcon‐
Lang & DiMichele, 2010). Sites of abundant, well‐
preserved and diverse fossils, in many cases, can 
be related to IVF erosion and subsequent depo­
sition (Feldman et al., 1993). Similar features 
termed ‘incised channel fills’ have also been 
described (Falcon‐Lang et al., 2009).
OBSERVATIONAL DATA SUPPORTING 
CATACLYSMIC BURIAL
Recognition of tidal sedimentation within GSWs
In the late 1980s and early 1900s, cyclic (‘tidal’) 
rhythmites were described from GSWs exposed 
within coal mines in south‐central Indiana (Kvale 
et al., 1989; Kvale & Archer, 1990; Archer & Kvale, 
1993; Batemann, 1992) and north‐eastern Illinois 
(Kuecher et al., 1990). These include essentially 
planar to low‐angle, heterolithic rhythmites 
(Fig.  3A) that consist of low‐angle, thinly inter­
laminated fine‐grained sandstone and gray shale 
(Fig.  3B). Since their initial discovery, tidally 
influenced sedimentation has been recorded in 
many coal‐bearing sections, including coals much 
older than those described herein; and from other 
coal basins in the eastern U.S. (Greb & Archer, 
1995; Gastaldo et al., 2004a).
Where sediment accumulation was extremely 
rapid, the laminae within the rhythmites can 
exhibit a variety of small‐scale cyclicity. The most 
common are neap‐spring tidal bundles There are a 
number of analogues for such rhythmites and they 
have been documented within modern, hyper­
tidal settings (Tessier et al., 1989; Dalrymple & 
Makino, 1989; Dalrymple et al., 1991, 2012; 
Tessier, 1993; Tessier et al., 1995; Archer, 2004, 
2013). Ancient counterparts of tidal rhythmites 
exhibiting neap‐spring cycles are also common 
throughout the geologic column (Archer, 1996a). 
Within inclined heterolith stratifications (IHS), 
sand‐rich foresets are capped by thin mud drapes 
(Fig 3B).
Despite the strong imprint of tidal periodici­
ties, geochemical evidence suggests that some 
deposition occurred within freshwater settings 
(Kvale & Mastalerz, 1998). The sparse fauna of 
GSW deposits, including pectinoid bivalves, lin­
guloid brachiopods and the branchiopod Leaia 
tricarinata, are suggestion of fresh to brackish‐
water settings.
Due to the great extent of the supercontinent of 
Pangaea, palaeofluvial systems could easily have 
been of a similar magnitude, or larger, scale than 
the modern Amazonian system (Archer & Greb, 
1995). Similar low salinity to freshwater condi­
tions have been documented in modern hyper­
tidal analogues of rhythmites (Archer, 2004, 2013). 
Today, the largest area of freshwater tidal flats is 
within the lower reaches of the Amazon River. 
Here, tidal effects extend for more than 1000 km 
inland and also extend out onto the continental shelf 
(Archer, 2005). In addition to the globe‐spanning 
continent of Pangaea, the globe‐spanning ocean of 
Panthalassa could have resonated strongly with 
the tide‐raising forces of the moon and sun (Archer, 
1996b). This could have resulted in the develop­
ment of hypertidal conditions along the coastal 
areas of Pangaea.
Cataclysmic burial of Pennsylvanian Period coal swamps in the Illinois Basin 221
Upright plants, trees and forests
Upright forests of in situ trees have attracted a great 
deal of attention since the beginning of the formal 
study of Pennsylvanian geology and the number of 
mentions in the literature is very large (DiMichele 
& Falcon‐Lang, 2011, 2012). Trees are so common 
in some mining regions that miners have given 
them nicknames such as ‘kettlebottoms’ and treat 
them as a serious hazard; the plug of rock within an 
upright fossil stump is prone to fall out of the mine 
roof (Chase & Sames, 1983). In the Illinois Basin 
such upright trees are commonly found almost 
exclusively within GSW facies. Large trees, ranging 
up to nearly 2 m in diameter, are often observed in 
the high walls of strip (opencast) mines. These 
trees seem to be concentrated along channel mar­
gins and the preserved stumps commonly attain 
vertical heights of 2 to 3 m. Upright, in situ trees 
and smaller plants (Fig. 4A) are common in GSW 
roof facies. Such in‐place fossil plants are totally 
absent in mines with black shale or limestone roof 
facies. In situ fossil forests have been reported from 
a number of sites directly overlying coals 
(DiMichele & Nelson, 1989; DiMichele et al., 2009). 
Within the Illinois Basin the more extensive 
entombed forest includes hundreds of upright trees 
that can be observed within single, underground 
mines (DiMichele & DeMaris, 1987; DiMichele 
et al., 2009). Upright plants are also common above 
laterally equivalent coals in the Appalachians 
(Chase & Sames, 1983; Gastaldo, et al., 1995; 
DiMichele et al., 1996; Gastaldo et al., 2004b).
The most commonly encountered standing trees 
(Fig.  4A) are arborescent lycopsids or ‘club‐
mosses’, an extinct group of giant trees related to 
the modern, diminutive Isoetes (Bateman, 1992; 
Phillips & DiMichele, 1992; DiMichele & DeMaris, 
1985; DiMichele & Phillips, 1994). Giant lycops­
ids were particularly prone to upright, in situ 
preservation because of their unique construction. 
The stems were supported by a thick rind of 
decay‐resistant bark (Boyce et al., 2010); such that 
water transport and support functions were 
entirely separated. This is quite different from 
modern seed‐plant trees, where these functions 
are combined in the wood. As a consequence, the 
internal tissues of the ancient tree trunks decayed 
rapidly during or after tree maturation, producing 
a natural, cylindrical mould into which sediment 
could accumulate. The infilling sediments sup­
ported and preserved the hollow stump as cast 
and mould. The bark is commonly coalified. 
Lycopsid trees had an extensive, shallowly pene­
trating but tenacious rooting system, known as 
‘stigmaria’. These stout roots radiated horizon­
tally up to at least 15 m from base of the trunk. 
Outrigger‐like roots provided secure support for 
these tall (30 to 40 m) trees that often grew in soft 
A B
1
cm
Fig. 3. (A) Cyclical, tidal rhythmite from Creek Paum Mine in southern Illinois. Neap‐spring cycles and perigean‐spring 
cycles are evident (Archer & Greb, 2011). (B) Close‐up of mine wall showing inclined heterolithic stratification. Scale in 
cm and decimetres.
222 A. W. Archer et al.
substrates, such as uncompacted peat. Thus, 
lycopsids did not uproot and fall over like modern 
seed‐plant trees. Despite several decades of mine‐
based research, none of the authors has ever seen 
an uprooted lycopsid trunk, nor have any of their 
field‐experienced colleagues. Such trees would 
have stood upright for only a short period of time 
before decay eliminated the organic rind. Thus, 
all reported occurrences provide convincing evi­
dence of rapid burial.
In addition to the lycopsids, smaller calamitean 
stems (Fig.  4B and C) are common and formed 
dense, monospecific stands (DiMichele et al., 
2009). This group is related to modern Equisetum 
and includes extant horsetails and scouring 
rushes. Calamiteans had, even during life, a hol­
low central stem. After death, the decay of tissue 
partitions within the stem permitted the entry of 
sediment. The result was upright preservation 
with a remaining thin coaly rind. Despite small 
stem diameters, calamiteans have been preserved 
to heights of several metres (DiMichele et al., 
2009) (Fig. 4B). Thus, a much smaller and archi­
tecturally very different plant also provides 
 evidence of rapid burial within GSW facies.
Finally, much smaller scale but effectively in situ 
plants have also been recognised in association 
with upright lycopsid stumps (Gastaldo et al., 
2004a; DiMichele et al., 2007). These smaller plants 
are generally represented by clumps of ground 
cover and by the stems and large foliar fragments of 
seed ferns and marattialean (true spore‐bearing) 
ferns. Stems and large leaves of these plants do not 
form natural hollows during natural decay and 
would have been subject to rapid decay and degra­
dation if exposed to oxidation. Thus, once the 
stems fell, rapid burial was necessary to isolate the 
plant remains from potential aerobic decay and 
Coal-smut layer
1 
m
C
BA
Fig. 4. (A) 3.3 m‐tall trunk of an upright lycopod within the highwall of Creek Paum mine. Upright trunk is estimated to be 
5.5 m in height. Photograph provided by Barry Sargent of Knight Hawk Coal. (B) Upright Calamites in shale overlying 
Murphysboro Coal in Jackson County, Illinois. (C) Tracing of B showing location of Calamites above a clastic‐rich, coaly‐
shale layer (‘coal smut’).
Cataclysmic burial of Pennsylvanian Period coal swamps in the Illinois Basin 223
destruction (Gastaldo, 2010). The famous Mazon 
Creek fauna of soft‐bodied organisms from north­
ern Illinois occurs in siderite concretions within a 
GSW overlying the Colchester Coal (Shabica & 
Hays, 1997). The preservation of such fossils 
demands rapid burial.
Thus, to conclude, a great variety of sizes of  fossil 
plants have been preserved in place and encased 
within rhythmites. The plants are diverse and 
ranged from 30 m‐tall lycopsids, several m‐tall sphe­
nopsids and smaller‐scale ground foliage including 
ferns. Very high sedimentation rates, related to the 
local and regional development of hypertidal con­
ditions, allowed the rapid creation of accommoda­
tion space and the entombing of plants. Finally, the 
grown and decay of Gondwanaland glaciations, 
particularly during periods of deglaciations also 
created abundant accommodation space for 
extended periods of deposition.
PROCESSES THAT CAN RAPIDLY 
INCREASE ACCOMMODATION SPACE
Peat compaction
A number of workers have tried to portray a pal­
aeoenvironmental setting in which upright plants 
could be commonly preserved immediately above 
coal seams. It is widely accepted that the conver­
sion of peat to coal involves some degree of com­
paction and dewatering. However, the timing of 
compaction is not well understood. Making a sim­
plistic assumption that there was minimal internal 
compaction during peat accumulation, a 1 m‐thick 
coal could have originally been a 10 to 20 m‐thick 
peat. Assuming that approximately half of com­
paction occurred in the lower, buried portion of 
the peat pile, then the remaining compaction of 
the entire peat column could generate from 5 to 
10 m of sediment accommodation space. This 
value falls within the measured heights of upright 
lycopsids discussed above. Compaction rates for 
various types of peats have been estimated to range 
as low as 1.4 : 1 up to rates of 30 : 1 (Ryer & Langer, 
1980). Conversely, post‐burial compaction, on the 
order of 3 : 1 at the most, was proposed by Wanless 
(1964) and Nadon (1998). Peat compaction could 
certainly generate some degree of accommodation 
space (Kvale & Archer, 1990), but whether or not 
the peat could compact in a short‐enough time­
frame is open for debate. Margins of coal beds 
commonly exhibit what appears to be significant 
erosion (Fig. 5). This style of erosion suggests that 
significant peat compaction had already occurred 
prior to GSW deposition.
Occurrences of large, upright trees indicate that 
the peat would need to have compacted by several 
metres prior to the influx of the GSW. In addition, 
the IHS indicates that 2 to 4 m of water had to have 
been present so that the bar forms could migrate. 
Thus, a simple model invoking autocompaction 
alone does not seem to offer a viable explanation.
GSW rhythmites that directly overlie coal have 
a high degree of variability. In some parts of a 
mine, low‐angle rhythmites are common (Fig. 6) 
and such rhythmites tend to contain relatively 
small upright plants. Close to the palaeochannels, 
GSW rhythmites are noticeably more thickly lami­
nated, particularly in the lower parts of the sec­
tion (Fig.  7). Inferred rates of vertical or lateral 
accretion would be decimetres or metres per 
month. Such rates commonly occur in modern 
hypertidal estuaries (Archer, 2013).
Despite the lingering uncertainties regarding 
the magnitude of Pennsylvanian peat compaction, 
this process, over regional scales, could provide a 
significant generation of accommodation space 
for the preservation of rapidly deposited, hyper­
tidal lithofacies. Much more work on this topic 
will be necessary in order to understand the mag­
nitudes and rates of both the coals as well as the 
enclosing sediments.
Faulting
Abrupt submergence caused by fault movements 
has been invoked as a mechanism to explain pres­
ervation of upright trees in the fossil record 
(Gastaldo et al., 2004a). While examples can be 
cited from the modern record, investigations in 
the Illinois Basin disclose that tectonic move­
ments played only a peripheral role in the burial 
and preservation of standing vegetation.
Similar to most of the Midcontinent and west­
ern United States, the Illinois Basin was tectoni­
cally active during the Pennsylvanian. This 
activity was part of the Ancestral Rocky Mountains 
(ARM) orogeny. Recurrent displacements along 
deep‐seated strike‐slip and high‐angle reverse 
faults, with attendant folding of sedimentary 
cover, characterize this event. Most ARM struc­
tures in the Illinois Basin trend north to north‐
west and take the form of monoclines and belts of 
domes or anticlines at Pennsylvanian level. Chief 
among these are the Du Quoin Monocline, the La 
224 A. W. Archer et al.
Salle Anticlinorium and the Salem and Louden 
Anticlines (McBride & Nelson, 1999).
The structure of the Illinois Basin has been 
mapped in great detail, using the records of tens of 
thousands of exploration holes for oil, gas and 
coal along with seismic reflection and other geo­
physical surveys (Nelson, 1991; 1995; Nelson & 
Bauer, 1987; Kolata & Nelson, 1991). As a result, 
the structural framework of this basin is very thor­
oughly understood. Moreover, extensive and 
detailed mapping of faults and other structural 
disturbances has been carried out in underground 
coal mines (Krausse et al., 1979; Nelson, 1981, 
1983). Some of this underground mapping encom­
passes fields of fossil tree stumps; and the rela­
tionship of these fossils to regional features has 
been considered carefully.
On the grand scale, palaeochannels associated 
with GSW deposits and fossil trees tracked along 
trends of maximum basin subsidence. Locally, 
contemporaneous fault movements influenced 
channel trends. For example, the southern 
 segment of the Walshville channel in the Herrin 
Coal parallels the eastern, downthrown side of the 
Du Quoin Monocline. In situ fossil stumps have 
been observed overlying the Murphysboro Coal in 
an area of south‐western Illinois where thick coal 
and attendant GSW lie on the downthrown side of 
a monocline (Nelson et al., 2011). A fossil forest 
above the Herrin Coal of east‐central Illinois 
occurs on the downthrown side of an inferred 
north‐east‐striking basement fault (DiMichele 
et al., 2007). However, the two best‐known palae­
ochannels, the Walshville and the Galatia, each 
A
B
20 cm
Fig. 5. (A) Frayed and abraded area of coal in an underground mine wall and (B) interpretation. Matrix sediment consists 
of basal grey‐shale wedge lithofacies. The original peat must have been significantly compacted before the erosional event. 
This event was apparently penecontemporaneous with the deposition of the gray shale. Very thin coaly stringers are prob­
ably individual, coalified leaves and branches. Owing to the apparently resistant (felted) nature of the peat, the degree of 
erosion is remarkable and perhaps is related to event of significant energy, such as the passage of tidal bores.
Cataclysmic burial of Pennsylvanian Period coal swamps in the Illinois Basin 225
meandered for hundreds of kilometres across the 
basin are largely independent of mapped faults. In 
most of the mines where we have observed stand­
ing fossil trees, no tectonic disturbance of the coal 
and enclosing strata can be detected.
To summarise, rapid or sudden earth movements 
may have contributed to the burial of standing trees 
in isolated instances. However, the large majority 
of fossil forests in the Illinois Basin cannot be 
related to contemporaneous fault movements.
DYNAMICS OF DEGLACIATION
Applying Neogene models to Pennsylvanian 
Period settings
Dynamics of the deglaciation at the close of the 
Pleistocene are exceedingly complex and the 
study of global‐climate changes is a very active 
area of on‐going research. A number of calibrated 
data sets have been generated using proxy, palae­
oclimatic information derived from a disparate 
variety of sources. These datasets, which include 
long ice cores, tree‐ring measurements, sub­
merged reef corals and speleothems, to name a 
few, provide very important constraints on the 
evaluation of climate‐change and sea‐level mod­
els (Milne et al., 2005). Detailed understanding of 
Pleistocene processes can provide hypothetical 
models that can be compared to Pennsylvanian 
palaeoenvironments.
There are relatively direct linkages between 
global warming, deglaciation and sea‐level 
changes. However, rapid changes in sea‐level are 
not necessarily a direct response to climatically 
Coal
A
B
up up
up
1 
m
Fig.  6. (A) Mine‐wall photograph and (B) interpretation 
(red lines) of cm‐scale rhythmic bedding. Top of the Herrin 
Coal is exposed in the lower part of the image. Small 
upright plants (‘up’) are common along the top of the coal 
seam. In the lower left is an in‐place, small tree trunk 
(rooted in underlying coal). Soft‐sediment deformation 
around this trunk suggests the contemporaneous nature of 
plant growth and rhythmite deposition. This surface has 
been long‐wall mined and thus has a slightly undulose 
 surface produced by the cutter blades.
A
B
1
2
3
4 5 6
dm
Fig. 7. (A) Mine‐wall photograph and (B) interpretation of 
cross bedding and soft‐sediment deformation. Planar sand 
beds (30 cm‐thick) occur across the top the photograph. In 
places, these planar beds and other areas are obscured by 
white, limestone dust. This was sprayed on mine walls to 
reduce fire danger. Six individual sets of crossbeds are evi­
dent and these are separated by zones of slumping and 
extreme soft‐sediment deformation.
226 A. W. Archer et al.
induced melting. Instead, periods of particularly 
rapid sea‐level rise might relate much more 
directly to glacial hydrology (Shaw, 1989; Douglas, 
1992; Alvarez et al., 2011) than to simple, linear 
climate change.
Ice‐rafted debris and Heinrich events
Within the late Pleistocene and Holocene, a num­
ber of Ice‐Rafted‐Debris (IRD) events have been 
recognised. IRD zones are found within cores 
taken from continental shelves and deep‐ ocean 
areas. These zones contain sand‐sized sediment. 
As the background sedimentation was very fine 
grained, the occurrence of the thin, coarser zones 
is problematic. The coarser zones have been inter­
preted to be the result of armadas of icebergs that 
melted and dumped their load of coarser sediment.
Heinrich events are particularly well‐developed 
IRD events and have an average duration of about 
750 years (Maslin et al., (2001). Roche et al. (2004) 
suggested that Heinrich event 4, which lasted for 
about 250 years, resulted in a 2 m sea‐level rise. 
These events are related to global climatic fluctua­
tions that coincide with the destruction of north­
ern hemisphere glaciers. Heinrich events were 
produced by the release of a large volume of ice­
bergs from tide‐water glaciers. These events had 
an apparently abrupt onset that may have occurred 
within a few years (Maslin et al., 2001). The 
Younger Dryas can be correlated with the young­
est Heinrich Event (H0, see Fig. 8), which occurred 
at c. 12 ka. H1, the second Heinrich event occurred 
from 17 ka (Hemming, 2004) to 14 ka (Vidal, 1999). 
Vidal et al. (1999) discuss a linkage between such 
events in both the North and South Atlantic 
oceans.
Palaeomegafloods
The Last Glacial Maximum (LGM) was approxi­
mately 23 to 19 ka ago. The subsequent deglacia­
tion included a great number of megafloods. The 
megafloods included the releases of meltwater 
from subglacial lakes as well as cataclysmic 
 failure of large ice‐based or morainal dams. To 
adequately describe the scale of these titanic 
 discharges an oceanography term, the ‘Sverdrup’ 
unit, has been commonly applied. One Sverdrup 
(Sv) is equivalent to 106 m3 s−1. The entire average 
input of freshwater from the world’s rivers into 
the ocean is approximately equal to 1 Sv. By com­
parison to modern large rivers, the freshwater 
 outflow of the Amazon River is approximately 
0.3 Sv. The Meghna/Padma/Brahmaputra system 
and Chanjiang (Yangtze) have discharges of 
0.05 Sv and 0.04 Sv, respectively. For comparison, 
the North American Mississippi River system has 
 discharge of 0.02 Sv; thus it would require the 
simultaneous discharge of about 50 Mississippi‐
size rivers to equal 1 Sv.
In the following discussion of megafloods, we 
will first discuss the oldest and then proceed to 
the youngest events (Fig. 8). Following the LGM, 
some of the oldest megafloods were located in the 
region of Eurasia. Around 18 ka, large flows from 
Eurasian meltwater outbursts were spilling into 
the Aegean Sea (Baker, 2008).
Perhaps the best‐studied series of megafloods 
occurred in the state of Washington in the north‐
western U.S. The palaeofloods are commonly 
referred to as the ‘Lake Missoula’ floods or as 
the  ‘Spokane Flood.’ Tremendous palaeofloods 
created an erosional landscape termed the 
‘Channelled Scablands’ (Bretz, 1923; 1969). The 
Missoula floods were postulated to have been a 
single megaflood event (Bretz, 1969; Shaw et al., 
1999). Other workers have suggested multiple 
floods (Waitt, 1980). Benito & O’Conner (2003) 
suggested that some Lake Missoula discharges 
exceeded 3 Sv and that the largest single flood had 
a discharge near 10 Sv. This range of floods would 
have been equivalent to 10 to 33 times the dis­
charges of the modern Amazon River system. 
Theoretical discharge models suggest that the lake 
could have been totally emptied into the ocean in 
about ‘100 days’ (Shaw et al., 1999, p. 608).
Within Arctic Canada, the Laurentide Ice 
Sheet formed a 3 km‐thick dome over the Hudson 
Bay area approximately at 8.5 ka (Clark & Mix, 
2002). During the on‐going deglaciation, the 
moraine‐dammed and ice‐dammed megalakes 
included Lake Agassiz. As the thick ice sheet 
melted, approximately at 8.45 ka, megafloods 
emanating from this glacial megalake system 
included the most abrupt and widespread global‐
cooling event that has occurred over the last 
100 ka (Clarke et al., 2003, p. 923). Maximum dis­
charges ranged from 5 to 10 Sv and the duration 
of the flow may have lasted ‘less than one year’ 
(Clarke et al., 2003). The 8.2 ka cooling event is 
probably the combined result of these meltwater 
pulses. In Asia, megaflood discharges have been 
estimated to have been 11 Sv (Herget & Agatz, 
2003). Very little is known about these systems at 
this time.
Cataclysmic burial of Pennsylvanian Period coal swamps in the Illinois Basin 227
Melt‐water Pulses (mwp)
Modern rates of sea‐level rise have been estimated 
to average about 1.7 to 1.8 mm yr−1 (Douglas, 1992; 
Church et al., 2004; Holgate & Woodworth, 2000). 
During the last deglaciation, short intervals exhib­
ited rapid, sea‐level rise and are referred to as 
‘melt‐water pulses’ (‘mwp’). Even without a con­
current period of warming, rapid rises in sea‐level 
could trigger: (1) destabilization of ice shelves, 
(2) collapse of continental‐scale ice sheets and (3) ini­
tiate the release of tremendous volumes of glacial‐
megalake and subglacial meltwater (Weaver et al., 
2003). The mwp events were apparently very 
short and ranged from ‘10 to 103 years’ (Gornitz, 
2009, p. 887) and involved rapid changes in tem­
perature and salinity of the oceans. Smaller scale 
modern events are termed jökulhlaups’ and are 
caused by subglacial melting or release of ice‐
dammed meltwater. Contemporary examples have 
been described as ‘self‐dumping glacial‐dammed 
lakes’ (Clague & Mathews, 1973, p. 501).
The most widely accepted meltwater pulses are 
designated as ‘wmp‐1A’ and ‘wmp‐1B’ (Fig.  8). 
These pulses have been discussed by many 
authors (see summary in Gornitz, 2009, table S1, 
p. 890). Event mwp‐1A occurred from about 14.5 
to 14.2 ka (Weaver et al., 2003). Sea‐level rose at 
rates exceeding 2 cm yr−1 or 20 m over a period of 
1.0 ka (Fairbanks, 1989) whereas Weaver et al. 
(2003) estimated an average rate of rise of about 
4 cm yr−1. Based upon contemporary rates of sea‐
level rise of about 2 mm yr−1, the estimated rates of 
flow for wmp‐1A were 200 to 400 times quicker 
(Douglas, 1992; Holgate & Woodworth, 2008).
Other pulses, such as mwp‐1Ao and mwp‐1C 
(see Fig. 8) are far less widely noted. Event mwp‐
1Ao would be the oldest meltwater pulse and it 
ranged from about 19.2 ka to 19.0 ka (Yokoyama 
et  al., 2000; Clarke et al., 2003). This pulse 
occurred within the youngest portion of the LGM. 
On the other hand, mwp‐1C is the youngest major 
pulse and occurred at about 7.6 ka. This pulse 
caused a rise in sea‐level of 4 cm yr−1 (Cronin et al., 
2007; Blanchon & Shaw, 1995). Older estimates 
for the timing of this pulse range from 8.2 ka 
(Törnqvist et al., 2004) down to 7.6 ka (Blanchon & 
Shaw, 1995).
Comparison of Late Pennsylvanian and 
Late Cenozoic analogues
There are many similarities between Late 
Palaeozoic, coal‐bearing rocks discussed herein 
and Late Cenozoic deglaciational events that have 
been compared and discussed herein. Both strati­
graphic intervals occurred during extended peri­
ods of continental‐scale cycles of glaciation and 
deglaciation. Based upon the observations dis­
cussed above, a typical Pennsylvanian grey‐shale 
wedge (GSW) could have been initiated by a mwp 
event mechanically similar to Neogene events. A 
rapid rise in Pennsylvanian sea‐level would have 
resulted in large, horizontal inland shifts of the 
coastline. The resultant transgression of an epi­
continental basin, such as the low‐slope Illinois 
Basin, would have quickly flooded coastal parts of 
widespread cratonic peats and rapidly progressed 
inland along riverine corridors. Initial generation 
of accommodation space could be related to peat 
compaction. Deposition of mud‐rich laminae and 
Lakes Agassiz-Ojibway
Eurasian lakes
Lake Missoula
–140
–120
–100
–60
–40
–20
0
–80
20 15 10 5 0
Years before present (×10)3 
R
el
at
iv
e 
se
a-
le
ve
l (
m
)
mwp–1A
mwp–1Ao
mwp–1B
mwp–1C
Younger Dryas
H1H2 H0
LGM
Fig.  8. Selected deglaciational events related to global 
changes in sea‐level from 23 ka to the present (modified 
from Gornitz, 2009). Time range of the last glacial maxi­
mum (LGM) is based upon Clark & Mix (2002). Timings of 
meltwater‐water pulses (mwp) are from Gornitz (2009). 
Megafloods related to large freshwater fluvio‐glacial melt­
water outbursts include: Eurasian lakes, outflows from 
Lake Missoula and discharges from the Lake Agassiz/
Ojibway complex. Heinrich Events (H1 and H2) related to 
ice‐rafted debris; H0 can be roughly equated to the Younger 
Dryas.
228 A. W. Archer et al.
mud‐draped IHS, following the rapid compaction 
of the upper peat, resulted in slower and longer‐
term dewatering of the entire, laterally extensive 
peat bodies. Following this initial and internal 
peat compaction, sea‐level rise related to a mwp 
could have allowed continued rapid deposition of 
tidal facies overlying the peat mires.
This scenario explains the initial and cataclys­
mic sedimentation that encased the upright plants. 
As the accommodation space was filled, there 
would be a shift to gradually decreasing sedimen­
tation. Such observations are consistently seen 
within single mines and also in the repeatedly 
stacked ‘cyclothems’ that characterize the Illinois 
Basin coal measures. This depositional scenario 
also explains the common co‐occurrence of thick 
coals and an overlying GSW. The thickest peats 
had a greater potential for internal dewatering and 
a higher potential for significant compaction.
The magnitude of the control of GSW deposi­
tion by mwp and Heinrich dynamics on the 
extremely flat landscape could have been very 
large. The botanical and sedimentological evi­
dence demand rapid sedimentation within the 
lower GSW. The commonality of the upright trees, 
suggests that a synergistic combination of: (1) peat 
compaction, (2) mwp and Hienrich events and 
megafloods; and (3) rapid tidal sedimentation 
could have been a tipping point regarding the 
 termination of peat accumulation. Over much 
longer periods of time and of a much smaller rate, 
a protracted regional to global transgression could 
have been driven by the processes related to 
Pangaean deglaciation.
CONCLUSIONS
The Late Palaeozoic encompasses the longest last­
ing glacial episodes that occurred during the 
Phanerozoic Eon. Within Pennsylvanian‐age coals 
of the Illinois Basin a number of features can be 
interpreted to have been the result of coastal 
flooding and cataclysmic burial of mires by tidal‐
estuarine sedimentation. The dramatic flooding 
occurred during periods of active peat accumula­
tion and fossil forests comprised of upright trees 
have been widely and spectacularly preserved.
The rapidity of the tidal‐estuarine sedimenta­
tion was aided by a concurrent generation of suf­
ficient accommodation. Several different processes 
have been put forth to explain the forests of upright 
trees. These include: (1) peat dewatering and 
 compaction, (2) local to regional fault‐related sub­
sidence, or (3) dramatic, short‐term rises in ancient 
sea‐level changes related to glacio‐eustacy. The 
notably and repetitious occurrences of GSW facies 
includes their deposition directly overlying major, 
economic coals. There is a very consistent strati­
graphic occurrence of GSW facies that encased 
upright forests. These forests were growing in 
swamps that were subsequently converted to bitu­
minous coal. The stratigraphic repetition indicates 
that unusual local or even regional factors were 
not the primary, underlying drivers. Invoking a 
global‐scale, allogenic event of short duration 
appears to offer a more reasonable hypothesis.
Cenozoic glacial processes, which have occurred 
since the last LGM and throughout the ensuing 
deglaciation, indicate that sea‐levels did not rise 
in a slow and uniform manner. During specific 
short‐term intervals, melt‐water pulses (mwp) 
resulted in very rapid and short‐term rises of 
global sea‐level. Some mwp events can be corre­
lated to specific events of cataclysmic flooding 
caused by fluvio‐glacial megafloods, such as those 
related to the megafloods released from Lake 
Missoula. It is suspected that similar large‐scale 
mwp could have been common during Gondwana 
deglaciations. This simple mwp‐based model 
could explain the common preservation of upright 
fossil forests within GSW that were originally 
rooted within the underlying coal beds.
ACKNOWLEDGEMENTS
Many persons and entities allowed access to and 
information regarding the underground and sur­
face mines discussed in this manuscript. Without 
access to active mines, this research would not 
have been possible. Gregory M. Molinda (CDC/
NIOSH/PRL) provided some very useful photo­
graphic information from underground mines. 
WD acknowledges funding from the NMNU Small 
Grants Program to support fieldwork.
REFERENCES
Allgaier, G.J. and Hopkins, M.E. (1975) Reserves of the 
Herrin (No. 6) Coal in the Fairfield Basin in south­
eastern Illinois. Illinois State Geol. Surv. Circular, 
489, 31 pp.
Alvarez, S.J., Montoya, M., Ritz, C., Ramstein, G., Charbit, 
S., Dumas, C., Nisancioglu, K.H., Dokken, T. and 
Ganopolski, K.A. (2011) Heinrich event 1: an example 
Cataclysmic burial of Pennsylvanian Period coal swamps in the Illinois Basin 229
of dynamical ice‐sheet reaction to oceanic changes. 
Climate of the Past, 7, 1297–1306.
Archer, A.W. (2008) Cyclic sedimentation (cyclothem). 
In:  Encyclopedia of Paleoclimatology and Ancient 
Environments (Ed. V. Gornitz), pp. 226–228, Springer, 
Dordrecht, The Netherlands.
Archer, A.W. (1996a) Panthalassa: paleotidal resonance 
and a global paleo‐ocean seiche: Paleoceanography, 11, 
625–632.
Archer, A.W. (2004) Recurring assemblages of biogenic 
and physical sedimentary structures in modern and 
ancient extreme macrotidal estuaries. J. Coastal Res., 
43, 4–22.
Archer, A.W. (1996b) Reliability of lunar orbital periods 
extracted from ancient cyclic tidal rhythmites. Earth 
Planet. Sci. Lett., 141, 1–10.
Archer, A.W. (2005) Review of Amazonian depositional 
systems. Int. Assoc. Sedimentol. Spec. Publ., 35, 
17–39.
Archer, A.W. (2013) World’s highest tides: Hypertidal 
coastal systems in North America, South America and 
Europe. Sed. Geol., 284–285, 1–25.
Archer, A.W. and Feldman, H.R. (1995) Incised valleys 
and estuarine facies of the Douglas Group (Virgilian): 
implications for similar Pennsylvanian sequences in 
the U.S. Mid‐Continent. In: Sequence stratigraphy of 
the mid‐Continent (Ed N. Hyne) Tulsa Geological 
Society, Tulsa, Oklahoma, pp. 119–140.
Archer, A.W., Feldman, H.R., Kvale, E.P. and Lanier, W.P. 
(1994) Pennsylvanian (Upper Carboniferous) fluvio‐ to 
tidal‐estuarine coal‐bearing systems: delineation of 
facies transitions based upon physical and biogenic 
sedimentary structures. Palaeogeogr. Palaeoclimatol., 
Palaeoecol., 106, 171–185.
Archer, A.W. and Greb, S.F. (1995) An Amazon‐scale 
drainage in the early Pennsylvanian of Central North 
America: J. Geol., 103, 611–628.
Archer, A.W. and Greb, S.F. (2011) Hypertidal facies from 
the Pennsylvanian Period: Eastern and Western Interior 
Coal Basins, USA. In: Principles of tidal sedimentology 
(Eds R.A. Davis, Jr. and R.W. Dalrymple) pp. 421–436. 
Springer. The Netherlands.
Archer, A.W. and Kvale, E.P. (1993) Origin of gray‐shale 
lithofacies (‘clastic wedges’) in U.S. midcontinental coal 
measures (Pennsylvanian): an alternative explanation. 
In: Modern and Ancient Coal‐Forming Environments 
(Eds J.C. Cobb and B. Cecil), Geol. Soc. Am. Spec. Pap., 
286, 181–192.
Baker, V. (2008) Late Quaternary megafloods. In: 
Encyclopedia of paleoclimatology and ancient environ-
ments (Ed V. Gornitz) pp. 506–507. Springer, The 
Netherlands.
Bateman, R.M. (1992) Evolutionary‐developmental change 
in the growth architecture of fossil rhizomorphic lycop­
sids: scenarios constructed on cladistics foundations. 
Biol. Rev., 69, 527–597.
Benito, G. and O’Connor, J.E. (2003) Number and size of 
last‐glacial Missoula floods in the Columbia River val­
ley between the Pasco Basin, Washington and Portland, 
Oregon. Geol. Soc. Am. Bull., 115, 624–638.
Blanchon, P. and Shaw, J. (1995) Reef drowning during the 
last deglaciation: evidence for catastrophic seal‐level 
rise and ice‐sheet collapse. Geology, 39, 4–8.
Boyce, C.K., Abrecht, M., Zhou, D. and Gilbert, P.U.P.A. 
(2010) X‐ray photoelectron emission spectromicro­
scopic analysis of arborescent lycopsid cell wall com­
position and Carboniferous coal ball preservation. Int. 
J. Coal Geol., 83, 146–153.
Bretz, J.H. (1923) The Channeled Scablands of the 
Columbia Plateau. J. Geol., 31, 617–649.
Bretz, J.H. (1969) The Lake Missoula floods and the 
Channeled Scabland. J. Geol., 77, 505–543.
Bristol, H.M. and Howard, R.H. (1971) Paleogeographic 
map of the sub‐Pennsylvanian Chesterian (upper 
Mississippian) surface in the Illinois Basin. Illinois 
State Geological Survey Circular, 458, 16 p.
Bristol, H.M. and Howard, R.H. (1974) Sub‐Pennsylvanian 
valleys in the Chesterian surface of the Illinois Basin 
and related Chesterian slump blocks. Geol. Soc. Am. 
Spec. Pap., 148, 315–335.
Chase, F.E. and Sames, G.P. (1983) Kettlebottoms: their 
relation to mine roof and support: U.S. Bureau of Mines, 
Report of Investigations, 8785, 12 p.
Church, J.A., White, N.J., Coleman, R., Lambeck, K. and 
Mitrovica, J. (2004) Estimates of the Regional 
Distribution of Sea‐level Rise over the 1950–2000 
Period. J. Climate, 17, 2609–2625.
Clague, J.J. and Mathews, W.H. (1973) The magnitude of 
jökulhlaups. J. Glaciology, 12, 501–504.
Clark, P.U. and Mix, A.C. (2002) Ice Sheets and sea‐level of 
the Past Glacial Maximum. Quatern. Sci. Rev., 21, 1–7.
Clarke, G., Leverington, D., Teller, J. and Dyke, A. (2003) 
Superlakes, megafloods and abrupt climate change. 
Science, 301, 922–923.
Cronin, T.M., Vogt, P.R., Willard, D.A., Thunell, R., Halka, 
J., Berke and M., Pohlman, J. (2007) Rapid sea‐level rise 
and ice sheet response to 8, 200‐year climate event. 
Geophy. Lett., 34, L20603.
Dalrymple, R.W., Boyd, R. and Zaitlin, B.A. (1994) Incised‐
valley systems: origin and sedimentary sequences: 
SEPM Spec. Publ., 51, 391 p.
Dalrymple, R.W., Mackay, D.A., Ichaso, A.A. and Choi, 
K.S. (2012) Processes, morphodynamics and facies of 
tide‐dominated estuaries. In: Principles of Tidal 
Sedimentology (R.A. Davis Jr. and R.W. Dalrymple). 
Springer, pp. 79–107.
Dalrymple, R.W. and Makino, Y. (1989) Description and 
genesis of tidal bedding in the Cobequid Bay‐Salmon 
River estuary, Bay of Fundy, Canada In: Sedimentary 
Facies of the Active Plate Margin (Eds A. Taira and F. 
Masuda) pp. 151–177. Terra Publishing, Tokyo.
Dalrymple, R.W., Zaitlin, B.A. and Boyd, R. (1991) 
Estuarine facies models: conceptual basis and strati­
graphic implications. J. Sed. Petrol., 62, 1130–1146.
DiMichele, W.A. and DeMaris, P.J. (1985) Arborsecent lyco­
pod reproduction and paleoecology in a coal‐swamp 
environment of late Middle Pennsylvanian age (Herrin 
Coal, Illinois, U.S.A.). Rev. Palaeob. Palynol., 44, 1–26.
DiMichele, W.A. and DeMaris, P.J. (1987) Structure and 
dynamics of a Pennsylvanian‐age Lepidodendron for­
est: colonizers of a disturbed swamp habitat in the 
Herrin (No. 6) Coal of Illinois. Palaios, 2, 146–157.
DiMichele, W.A., Eble, C.F. and Chaney, D.S. (1996) A 
drowned lycopsid forest above the Mahoning coal 
(Conemaugh Group, Upper Pennsylvanian) in eastern 
Ohio, U.S.A. Int. J. Coal Geol., 31, 249–276.
230 A. W. Archer et al.
DiMichele, W.A. and Falcon‐Lang, H.J. (2011) Pennsylvanian 
‘fossil forests’ in growth (To assemblages): origin, tapho­
nomic bias and palaeoecological insights. J. Geol Soc. 
London, 169, 585–605.
DiMichele, W.A. and Falcon‐Lang, H.J. (2012) Calamitalean 
‘pith casts’ reconsidered. Rev. Palaeob. Palynol., 173, 
1–14.
DiMichele, W.A., Falcon‐Lang, H.J., Nelson, W.J., Elrick, S. 
and Ames, P. (2007) Ecological gradients within a 
Pennsylvanian forest: Geology, 35, 415–418.
DiMichele, W.A. and Nelson, W.J. (1989) Small‐scale spa­
tial heterogeneity in Pennsylvanian‐age vegetation from 
the roof shale of the Springfield Coal (Illinois Basin). 
Palaios, 4, 276–280.
DiMichele, W.A., Nelson, W.J., Elrick, S. and Ames, P.R. 
(2009) Catastrophically buried Middle Pennsylvanian 
Sigillaria and calamitean sphenopsides from Indiana, 
USA: What kind of vegetation was this? Palaios, 24, 
159–166.
DiMichele, W.A., Pfefferkorn, H.W. and Gastaldo, R.A. 
(2001) Response of Late Carboniferous and Early 
Permian plant communities to climate changes. Annu. 
Rev. Earth and Planet. Sci., 29, 461–487.
DiMichele, W.A. and Phillips, T.L. (1994) Paleobotanical 
and paleoecological constraints on models of peat for­
mation in the Late Carboniferous of Euramerica. 
Palaeogeogr., Palaeoclimatol, Palaeoecol., 106, 39–90.
Douglas, B.C. (1992) Global sea‐level rise, J. Geophys. Res., 
96, 6981–6992.
Fairbanks, R.G. (1989) A 17,000‐year glacio‐eustatic sea‐
level record: influence of glacial melting rates on the 
Younger Dryas event and deep‐ocean circulation. 
Nature, 342, 637–642.
Falcon‐Lang, H.J. (2004) Pennsylvanian tropical rainfor­
ests responded to glacial‐interglacial rhythms. Geology, 
32, 689–692.
Falcon‐Lang, H.J. and DiMichele, W.A. (2010) What hap­
pened to the coal forests during Pennsylvanian glacial 
phases? Palaios, 25, 611–617.
Falcon‐Lang, H.J., Nelson, W.J., Elrick, S., Looy, C.V., 
Ames, P.R. and DiMichele, W.A. (2009) Incised channel 
fills containing conifers indicate that seasonally dry 
vegetation dominated Pennsylvanian tropical lowlands. 
Geology, 37, 923–926.
Feldman, H.R., Archer, A.W., Kvale, E.P., Cunningham, 
C.R., Maples, C.G. and West, R.R. (1993) A tidal model 
of Carboniferous Konservat Laggerstätten formation: 
Palaios, 8, 485–498.
Gastaldo, R.A. (2010) Peat or no peat: why do the Rajang and 
Mahakam deltas differ? Inter. J. Coal Geol., 83, 162–172.
Gastaldo, R.A., H.W. Pfefferkorn and W.A. DiMichele 
(1995) Characteristics and classification of Carboniferous 
roof shale floras. In: Historical perspectives of early 
Twentieth Century Carboniferous paleobotany in North 
America (Eds P.C. Lyons, E.D. Morey and R.H. Wagner) 
Geol. Soc. Am. Mem., 185, 341–352.
Gastaldo, R.A., Stevanovic‐Walls, I.M. and Ware, W.N. 
(2004a) Erect forests are evidence for coseismic base‐
level changes in Pennsylvanian cyclothems of the Black 
Warrior Basin, U.S.A. In: Sequence stratigraphy, pale-
oclimate and tectonics of coal‐bearing stratigraphy (Eds 
J.C. Pashin and R.A. Gastaldo), AAPG Studies in 
Geology, 51: 219–238.
Gastaldo, R.A., Stevanovic‐Walls, I.M., Ware, W.N. and 
Greb, S.F. (2004b) Community heterogeneity of early 
Pennsylvania peat mires. Geology, 32, 693–696.
Gluskoter, H.J. and Hopkins, M.E. (1970) Distribution of 
sulfur in Illinois coals. In: Depositional environments in 
parts of the Carbondale Formation ‐ Western and north-
ern Illinois (W.H. Smith, R.B. Nance and R.G. Johnson). 
Illinois State Geol. Surv. Guidebook Series, 8, 89–95.
Gluskoter, H.J. and Simon, J.A. (1968) Sulfur in Illinois 
coals. Illinois State Geol. Surv. Circ., 432, 28 p.
Gornitz, V. (2009) Sea‐level change, post‐glacial. In: 
Encyclopedia of paleoclimatology and ancient environ-
ments (Ed. V. Gornitz) pp. 887–893. Springer, Dordrecht, 
The Netherlands.
Gradstein, F.M., Ogg, J.G., Schmitz, M.D. and Ogg, G.M. 
(2012) The geologic time scale. Elsevier, New York, 
1176 p.
Greb, S.F. Andrews, W.M., Eble, C.F., DiMichele, W., Cecil, 
C.B. and Hower, J.C. (2003) Desmoinesian coal beds of 
the Eastern Interior and surrounding basins: The largest 
tropical peat mires in earth history. In: Extreme deposi-
tional environments: Mega‐end members in geologic 
time (Eds M.A. Chan and A.W. Archer), Geol. Soc. Am. 
Spec. Pub., 370, 127–150.
Greb, S.F. and Archer, A.W. (1995) Rhythmic sedimenta­
tion in a mixed tide and wave deposit, eastern Kentucky, 
U.S.A. J. Sed. Res., B65, 96–106.
Hemming, S.R. (2004) Heinrich events: massive Late 
Pleistocene detritus layers of the North Atlantic and 
their global climate imprint. Rev. Geophys, 370, 
127–150.
Herget, J. and Agatz, H. (2003) Modelling ice‐dammed lake 
outburst floods in the Altai Mountains (Siberia) with 
HEC‐RAS. In: Palaeofloods, historical data and climatic 
variability: applications in flood risk assessment (Eds 
V.R. Thorndycraft, G. Benito, N.M. Barriendos and 
M.S. Llast) Madrid, Proceedings of the PHEFRA 
Workshop, Centro de Ciencias Medioamientales pp. 
177–181.
Holgate, S.J. and Woodworth, P.L. (2000) Evidence for 
enhanced coastal sea‐level rise during the 1990s. 
Geophys. Res. Lett., 31, L07305.1‐L07305.4.
Hopkins, M.E. (1968) Harrisburg (No. 5) Coal reserves of 
southeastern Illinois. Illinois State Geol. Surv. Circ. 431, 
25 p.
Kolata, D.R. and Nelson, W.J. (1991) Tectonic history of the 
Illinois Basin. AAPG Mem., 51, 25 p.
Kosanke, R.M., Simon, J.A., Wanless, H.R. and Willman, H.B. 
(1960) Classification of the Pennsylvanian strata of Illinois. 
Illinois State Geol. Surv. Report of Investigations, 214, 84 p.
Krausse, H.‐F., Damberger, H.H., Nelson, W.J., Hunt, S.R., 
Ledvina, C.T., Treworgy, C.G. and White, W.A. (1979) 
Roof strata of the Herrin (No. 6) Coal Member in mines 
of Illinois: their geology and stability: Illinois State 
Geological Survey, Illinois Minerals Note, 72, 53 p.
Kuecher, G.M., Woodland, B.G. and Broadhurst, F.M. 
(1990) Evidence of deposition from individual tides and 
of tidal cycles from the Francis Creek Shale (host rock to 
the Mazon Creek Biota, Westphalian D (Pennsylvanian), 
northeastern Illinois. Sed. Geol., 68, 211–221.
Kvale, E.P. and Archer, A.W. (1990) Tidal deposits associ­
ated with low‐sulfur coals, Brazil Fm. (Lower 
Pennsylvanian), Indiana. J. Sed. Petrol., 60, 563–574.
Cataclysmic burial of Pennsylvanian Period coal swamps in the Illinois Basin 231
Kvale, E.P., Archer, A.W. and Johnson, H.J. (1989) Daily, 
monthly and yearly tidal cycles within laminated silt­
stones of the Mansfield Formation (Pennsylvanian) of 
Indiana. Geology, 17, 365–368.
Kvale, E.P. and Mastalerz, M. (1998) Evidence of ancient 
freshwater tidal deposits. In: Tidalites: Processes and 
Products (Eds C.R. Alexander, R.A. Davis and V.J. 
Henry), SEPM Spec. Pub., 61, p. 95–107.
Maslin, J., Seidov, D. and Lowe, J. (2001) Synthesis of the 
nature and causes of rapid climate transition during the 
Quaternary. Geophys. Monogr., 126, 9–52.
McBride, J.H. and Nelson, W.J. (1999) Style and origin of 
mid‐Carboniferous deformation in the Illinois Basin, 
USA. Ancestral Rocky Mountains deformation. 
Tectonophysics, 305, 249–273.
Milne, G.A., Long, A.J. and Bassett, S.E. (2005) Modeling 
Holocene relative sea‐level observations from the 
Caribbean and South America. Quatern. Sci. Rev., 24, 
1183–1202.
Moore, R.C. (1964) Paleoecological aspects of Kansas 
Pennsylvanian and Permian cyclothems. In: Symposium 
on Cyclic Sedimentation (Ed D.F. Merriam) Kansas 
Geol. Surv. Bull., 169, 287–380.
Moore, R.C. (1935) Stratigraphic classification of the 
Pennsylvanian rocks of Kansas. Kansas Geol. Surv. 
Bull., 22, 256 p.
Nadon, G.C. (1998) Magnitude and timing of peat‐to‐coal 
compaction. Geology, 26, 727–730.
Nelson, W.J. (1981) Faults and their effect on coal mining 
in Illinois. Illinois State Geol. Surv. Circ., 523, 45 p.
Nelson, W.J. (1983) Geologic disturbances in Illinois coal 
seams. Illinois State Geol. Surv. Circ. 530, 52 p.
Nelson, W.J. (1995) Structural features in Illinois: Illinois 
State Geological Survey, Bulletin 100, 144 p.
Nelson, W.J. (1991) Structural styles in the Illinois Basin. 
AAPG Mem., 51, 209–246.
Nelson, W.J. and Bauer, R.A. (1987) Thrust faults in south­
ern Illinois Basin – result of contemporary stress? Geol. 
Soc. Am. Bull., 98, 302–307.
Nelson, W.J., Devera, J.A., Williams, L.M. and Staub, J.R. 
(2011) Bedrock geology of Oraville quadrangle, Jackson 
County, Illinois. Illinois State Geological Survey, Illinois 
Geologic Quadrangle Map IGQ Oraville‐BG, 2 sheets, 
scale 1:24,000.
Nelson, W.J., Smith, L.B. and Treworgy, J.D. (2002) 
Sequence stratigraphy of the Lower Chesterian 
(Mississippian) strata of the Illinois Basin. Illinois State 
Geological Survey Bulletin 107, 70 p.
Phillips, T.L. and DiMichele, W.A. (1992) Comparative 
ecology and life‐history biology of arborescent lycopods 
in Late Carboniferous swamps of Euramerica. Annals of 
the Missouri Botanical Garden, 79, 560–588.
Roche, D., Paillard, D. and Corgijo, E. (2004) Constraints on 
the duration and freshwater release of Heinrich event 4 
through isotope modeling. Nature, 432, 379–382.
Ryer, T.A. and Langer, A.W. (1980) Thickness change 
involved in the peat‐to‐coal transformation for a bitumi­
nous coal of Cretaceous age in central Utah. J. Sed. 
Petrol., 50, 987–992.
Shabica, C.W. and Hays, A.A. (1997) Richardson’s guide to 
the fossil fauna of Mazon Creek. Northeastern Illinois 
University, Chicago, 308 p.
Shaw, J. (1989) Drumlins, subglacial meltwater floods and 
ocean responses. Geology, 17, 853–856.
Shaw, J., Munro‐Stasiuk, M., Sawyer, B., Beaney, C., 
Lesemann, J‐E., Musacchio, A., Rains, B. and Yung, 
R.R. (1999) The Channeled Scabland: back to Bretz? 
Geology, 27, 605–608.
Tessier, B. (1993) Upper intertidal rhythmites in the Mont‐
Saint‐Michel Bay (NW France): perspectives for paleo­
reconstruction. Mar. Geol., 110, 355–367.
Tessier, B., Archer, A. W., Lanier, W. P. and Feldman, H. R. 
(1995) Comparison of ancient tidal rhythmites 
(Carboniferous of Kansas, U.S.A.) with modern ana­
logues (the Bay of Fundy and Mont‐Saint‐Michel, N.W. 
France). Int. Assoc. Sedimentol. Spec. Publ., 24, 
259–271.
Tessier, B., Monfort, Yt ., Gigot, P. and Larsonneur, C. 
(1989) Enregistreme des tidaux en accretion verticale, 
ples en baie du Mont‐Saint‐Michele et dans la molasses 
marine Miocene du basin de Digne. Bull. Soc. Geologie 
France, 5, 1029–1041.
Törnqvist, T.E., Bick, S.J., Gonzalez, J.L., van der Borg, I. 
and de Jong, A.F.M. (2004) Tracking the sea‐level sig­
nature of the 8.2 ka cooling event: new constraints 
from the Mississippi Delta. Geophys. Res. Lett., 31, 
L23309.
Vidal, L., Schneider, R.R., Marchal, O., Bickert, T., 
Stocker, T.F. and Wefer, G. (1999) Link between the 
North and South Atlantic during the Heinrich events of 
the last glacial period. Climate Dynam., 15, 909–919.
Waitt, R.B., Jr. (1980) About 40 last‐glacial Lake Missoula 
jökulhlaups through southern Washington. J. Geol., 88, 
653–679.
Wanless, H.R. (1964) Local regional factors in 
Pennsylvanian cyclic sedimentation. In: Symposium on 
cyclic sedimentation (Ed. D.F. Merriam). Kansas Geol. 
Surv. Bull., 169, pt. 2, 593–606.
Wanless, H.R. and Weller, J.M. (1932) Correlation and 
extent of Pennsylvanian cyclothems. Geol. Soc. Am. 
Bull., 43, 1177–1206.
Weaver, A. J., Saenko, O.A., Clark, P.U. and Mitrovica, J.X. 
(2003) Meltwater Pulse 1A from Antarctica as a trigger 
of the Bølling‐Allerød warm interval. Science, 299, 
1709–1713.
Weller, J.M. (1930) Cyclical sedimentation of the 
Pennsylvanian Period and its significance: J. Geol., 38, 
97–135.
Weller, J.M. (1931) The conception of cyclical sedimenta­
tion during the Pennsylvanian Period. Illinois State 
Geol. Surv. Bull, 60, 163–177.
Wilkinson, B.H., Merrill, G.K. and Kivett, S.J. (2003) 
Stratal order in Pennsylvanian cyclothems. Geol. Soc. 
Am. Bull., 115, 1068–1087.
Yokayama, Y., Lambeck, K., De Deckker P., Johnston, P. 
and Fifield, L.K. (2000) Timing of the Last Glacial 
Maximum from observed sea‐level minima. Nature, 
406, 713–716.
Zangerl, R. and Richardson, E.S. (1963) The paleoecologi­
cal history of two Pennsylvanian black shales. Fieldiana 
Geol. Mem., 4, 1–352.
Zeller, E.J. (1964) Cycles and psychology. In: Symposium 
on cyclic sedimentation (Ed. D.F. Merriam), Kansas 
Geol. Surv. Bull., 169, pt. 2, 631–636.