Volatile budget of Yellowstone magmas: investigating eruptive triggers and environmental effects of the largest explosive eruptions on earth

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Dr. Thomas R. Benson has been awarded an EAR postdoctoral fellowship to conduct research and educational outreach at the American Museum of Natural History in New York. The investigation will assess triggering mechanism(s) and environmental effects of large supervolcanic eruptions through analysis of the most recent three major eruptions at the Yellowstone Plateau Volcanic Field (Wyoming, Montana, and Idaho, United States). The PI will collect field samples and perform laboratory work on them to determine the abundances of volatile chemicals (H2O, S, F, Cl) present in the magmas before the eruptions and quantify the amounts lost to the atmosphere during the eruptions. This work will inform hazard assessments of supervolcanoes to local and regional communities. The resulting models will improve understanding on the effects of future eruptions to the global environment. In addition, 360 degree virtual reality videos of volcanic features at Yellowstone National Park will be created to make the park more accessible to the public and utilize outreach programs at AMNH to engage local high school and undergraduate students in scientific research. This investigation will be the first comprehensive study of volatile systematics in Yellowstone magmas, in particular those that lead to caldera-forming eruptions. The work will involve analysis of apatite phenocrysts, microphenocrysts, and inclusions within other minerals using SIMS to evaluate equilibrium magma volatile concentrations. SIMS, electron microprobe, and FTIR analyses of homogenized melt inclusions within quartz and pyroxene phenocrysts will also be used to constrain the volatile composition of the magmas. Relative crystallization or entrapment order of all analyzed phases will be determined using thermodynamic constraints and petrographic relationships to assess how the concentrations of volatile components changed in the magmas with time. Concentrations will be compared to values measured in degassed matrix glasses using SIMS, electron microprobe, and FTIR to quantify the amount of volatiles that may have been lost to the atmosphere during these eruptions.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.