The longevity of large upper crustal silicic magma reservoirs
Sarah E. Gelman et al., Dept. of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA. Posted online ahead of print 9 May 2013; http://dx.doi.org/10.1130/G34241.1.
Using numerical heat transfer models, Sarah E. Gelman and colleagues simulated the incremental assembly of upper crustal silicic magma reservoirs, the source of Earth's largest volcanic eruptions. Incorporating reasonable magma emplacement rates, complexity in thermal properties, and appropriate igneous phase diagrams, they demonstrate that these large reservoirs can remain continuously active for more than a million years in highly productive magmatic environments, while remaining more transient in lower flux regions. These results are consistent with volcanological, geochronological, and geophysical data obtained from various provinces (e.g., Taupo Volcanic Zone and the Southern Rocky Mountain Volcanic Field as long-lived, productive regions, while the Cascades arc hosts lower flux stratovolcanoes). This work supports recent models emphasizing the role of in situ upper crustal magma storage and differentiation in a crystal-rich environment ("mush zones"). This is a particularly provocative deepening in geoscientists' understanding of silicic magma systems because previous thermal modeling studies, which have incorporated fewer complexities than those addressed in this study, have been used as primary evidence against the "mush model." The results presented here are consistent with natural observations from multiple techniques and represent an important contribution toward predicting how and wher
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