Experimental phase equilibria of a Mount St. Helens rhyodacite: a framework for interpreting crystallization paths in degassing silicic magmas
نویسندگان
چکیده
منابع مشابه
Petrogenesis of Mount St. Helens Dacitic Magmas
The most frequent and voluminous eruptive Kurasawa, 1983], (4) partial melting of the lower crust products at Mount St. Helens are dacitic in composition, [e.g., Grant et al., 1984; Reid and Cole, 1983], and (5) although a wide variety of magma types (basalt to formation of compositional gradients in response to rhyodacite) is represented. To address the petrogenesis of convective and diffusive...
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Explosive eruptions involve mainly silicic magmas in which sulfur solubility and diffusivity are low. This inhibits sulfur exsolution during magma uprise as compared to more mafic magmas such as basalts. Silicic magmas can nevertheless liberate large quantities of sulfur as shown by the monitoring of SO2 in recent explosive silicic eruptions in arc settings, which invariably have displayed an e...
متن کاملThe origin of Mount St. Helens andesites
Smith, D. R. and Leeman, W. P., 1993. The origin of Mount St. Helens andesites. J. Volcanol. Geotherm. Res., 55: 271-303. Mount St. Helens volcano has intermittently produced mainly dacitic products but occasionally erupted a more diverse suite of lavas including basalts and andesites. Petrogenetic relations between these magmas provide insight into the dynamics of the subjacent magma system. M...
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In order to assess the effect of eruption rate on the surface morphology and degassing mechanisms of silicic lava flows, we studied surface characteristics and obtained water content and hydrogen isotopic values of samples from flows at the Mount St. Helens and Santiaguito lava domes. We compared the surface textures and inferred degassing processes to short-term extrusion rates and found that ...
متن کاملChemical patterns of erupting silicic magmas and their influence on the amount of degassing during ascent
We present a chemical model of magma degassing based on nine volatile species part of S-O-H-C-Fe-bearing rhyolitic melts. It is based on equilibrium, closed-system degassing, and does not take in account the crystallization of mineral phases. For given initial conditions at depth, the model calculates the gas composition as pressure decreases, as well as physical variables controlling conduit f...
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ژورنال
عنوان ژورنال: Contributions to Mineralogy and Petrology
سال: 2015
ISSN: 0010-7999,1432-0967
DOI: 10.1007/s00410-015-1160-5