Spatial Distribution, Longevity, and Evolution of Giant Magma Bodies: Tapping the Record in Crystal-rich Supereruptions

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Supereruptions eject hundreds to thousands of km3 of magma into the air in a matter of days to months. They are the ultimate demonstration that the Earth's crust is capable of storing large quantities of eruptible magma. Not only are they a potential threat to humankind, but they are also fascinating from a scientific standpoint. Some of the largest eruptions on record seem to tap deposits that are crystal-rich, very extensive, and remarkably homogeneous in composition. In this project, the investigator will explore several important questions related to crystal-rich magma bodies that feed supereruptions: How is magma organized in the shallow crust just prior to supereruptions? What are the conditions that promote accumulation of unusually high amounts of eruptible magma in the shallow crust? How do magma systems that feed supereruptions evolve to a state that leads to a supereruption? What are the timescales over which these magma bodies differentiate, stall, and erupt? It is expected that the project will lead to new and improved understanding of the evolution of supereruption-forming magma bodies, including clues to the processes leading to eruption. It will provide support for graduate students at Vanderbilt University, whose graduate program has a strong record of training women in Earth & Environmental Sciences (at least two female PhD students will be funded by the project). The project will also support participation of undergraduates in research through participation in Vanderbilt May-term field courses abroad that the PI has been offering since 2013. The project will support work that will foster new and existing international and national collaborations.This study will combine four main approaches: (1) Study of the spatial distribution of magmas using the geographic distribution of vents and other surface manifestations of magma localization (e.g. collapse areas), in combination with information from geobarometry, which will inform the depth at which magmas are stored; (2) The depths of magma extraction will be a focus of study using geobarometry to assess to what extent storage of eruptible magma takes place contiguously with crystal-rich material from which it is extracted; (3) The crystallization times of eruptible magmas will be investigated using geospeedometry of major and accessory phases; (4) The evolution of magmas will be explored combining the record preserved in rock textures, crystal zoning, and glass compositions with information that can be extracted from thermodynamic modeling using rhyolite-MELTS, including investigations of the processes that control magma eruptibility. Two main localities were selected for the detailed work: (a) Ora Caldera deposits in northern Italy; and (b) Whakamaru Group in the Taupo Volcanic Zone, New Zealand.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.