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Title: Rehydrated glass embayments record the cooling of a Yellowstone ignimbrite
Abstract Hydration fronts penetrate 50–135 μm into glassy rhyolite embayments hosted in quartz crystals from the Mesa Falls Tuff in the Yellowstone Plateau volcanic field. The hydration fronts occur as steep enrichments that reach 2.4 ± 0.6 wt% H2O at the embayment opening, representing much higher values than interior concentrations of 0.9 ± 0.2 wt% H2O. Molecular water accounts for most of the water enrichment. Water speciation indicates the hydration fronts comprise absorbed meteoric water that modified the original magmatic composition of the rhyolitic glass. We used finite difference diffusion models to demonstrate that glass rehydration was likely produced over a few decades as the ignimbrite cooled. Such temperatures and time scales are consistent with rare firsthand observations of decadal hydrothermal systems associated with cooling ignimbrites at Mount Pinatubo (Philippines) and the Valley of Ten Thousand Smokes (Alaska).  more » « less
Award ID(s):
2042173
PAR ID:
10538594
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Geological Society of America
Date Published:
Journal Name:
Geology
Volume:
52
Issue:
7
ISSN:
0091-7613
Page Range / eLocation ID:
507 to 511
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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