dc.contributor.author |
Andrews, Benjamin J. |
en |
dc.date.accessioned |
2015-04-20T15:15:57Z |
|
dc.date.available |
2015-04-20T15:15:57Z |
|
dc.date.issued |
2014 |
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dc.identifier.citation |
Andrews, Benjamin J. 2014. "Magmatic storage conditions, decompression rate, and incipient caldera collapse of the 1902 eruption of Santa Maria Volcano, Guatemala." <em>Journal of Volcanology and Geothermal Research</em>. 282:103–114. <a href="https://doi.org/10.1016/j.jvolgeores.2014.06.009">https://doi.org/10.1016/j.jvolgeores.2014.06.009</a> |
en |
dc.identifier.issn |
0377-0273 |
|
dc.identifier.uri |
http://hdl.handle.net/10088/25675 |
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dc.description.abstract |
Phase equilibria experiments and analysis of natural pumice and phenocryst compositions indicate the 1902 Santa Maria dacite was stored at ~ 140-170 MPa and 840-850 °C prior to eruption. H2O-saturated, cold-seal experiments conducted in vessels with an intrinsic log fO2 of NNO + 1 ± 0.5 show that the natural phase assemblage (melt + plagioclase + amphibole + orthopyroxene + Fe-Ti oxides + apatite) is stable from approximately 115-140 MPa at temperatures below ~ 825 °C, to ~ 840-860 °C at 150 MPa, to > 850 and 50 MPa and > 50 °C greater than experimental run conditions; precise estimates of magmatic conditions based solely upon amphibole composition are likely inaccurate. The experimental results and analysis of natural crystals suggest that although the natural amphiboles likely record a broad range of magmatic conditions, only the lower bounds of that range reflects pre-eruptive storage conditions. Comparison of Santa Maria microlite abundances with decompression experiments examining other silicic systems from the literature suggests that the 1902 dacite decompressed at a rate of ~ 0.005 to 0.01 MPa/s during the eruption. Applying the decompression rate with the previously described eruption rate of approximately 2-3 × 108 kg/s (Williams and Self, 1983; Carey and Sparks, 1986) to the conduit model CONFLOW reveals that the eruption conduit was dike-like with an along-strike length > 1 km. Despite depositing ~ 20 km3 of dacite tephra (equivalent to ~ 8.5 km3 magma), the 1902 eruption did not form an obvious caldera. This work suggests that collapse of the dike-like conduit terminated the eruption, preventing full caldera collapse. |
en |
dc.relation.ispartof |
Journal of Volcanology and Geothermal Research |
en |
dc.title |
Magmatic storage conditions, decompression rate, and incipient caldera collapse of the 1902 eruption of Santa Maria Volcano, Guatemala |
en |
dc.type |
Journal Article |
en |
dc.identifier.srbnumber |
127132 |
|
dc.identifier.doi |
10.1016/j.jvolgeores.2014.06.009 |
|
rft.jtitle |
Journal of Volcanology and Geothermal Research |
|
rft.volume |
282 |
|
rft.spage |
103 |
|
rft.epage |
114 |
|
dc.description.SIUnit |
NH-Mineral Sciences |
en |
dc.description.SIUnit |
NMNH |
en |
dc.description.SIUnit |
Peer-reviewed |
en |
dc.citation.spage |
103 |
|
dc.citation.epage |
114 |
|