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Posts by Keith D. Putirka

v13n1 Supplement Putirka

Back to Main Article Methods and Further Reading by Keith Putirka  Supplement to the February 2017 (v13n1) issue of Elements. Disclaimer: this table was not reviewed by Elements nor were its contents verified. DOWNLOAD: Methods and Further Reading (PDF) Methods Calculating Clinopyroxene and Amphibole Pressures Clinopyroxene pressure and temperature estimates use Eqns. P1 and T2 of…

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Down the Crater: Where Magmas are Stored and Why They Erupt

Magmas are erupted from a wide range of depths. Olivine compositions, for example, indicate magma storage in the lower crust and upper mantle, while clinopyroxene and amphibole record middle to upper crust storage. Pre-eruptive magmas also often cool by 100–300 °C, frequently at middle–upper crust depths, indicating clogged, ephemeral volcanic pathways. These coolings imply that mafic recharge is not a sufficient cause for eruption and that crystallization-induced vapor saturation is a more proximal eruption trigger. But an improved understanding of eruption mechanisms require precise identifications of what are herein termed “ultimate”, “proximal,” and “immediate” causes of eruption.

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