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Magmatic volatiles in explosive rhyolitic eruptions
Author(s) -
Eichelberger J. C.,
Westrich H. R.
Publication year - 1981
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl008i007p00757
Subject(s) - tephra , rhyolite , geology , magma , explosive eruption , geochemistry , volcano , magmatic water , melt inclusions , explosive material , petrology , mineralogy , volcanic rock , seismology , meteoric water , chemistry , hydrothermal circulation , organic chemistry
Obsidian clasts in rhyolitic tephra deposits preserve preemption magmatic volatile contents, providing a direct means for determining the volatile content of explosively erupted magmas. Small to moderate volume Plinian eruptions (10 −3 to 10 −1 km³) appear to be driven by 0.5‐1.0 wt.% volatiles, consisting dominantly of H 2 O with minor CO 2 . Analysis of obsidian from eruptive sequences consisting of tephra and flows indicates that this hydrous magma abruptly overlies magma with only 0.1‐0.2 wt.% H 2 O.