NSF Org:	EAR Division Of Earth Sciences
Recipient:	UNIVERSITY OF ALASKA FAIRBANKS
Initial Amendment Date:	July 12, 2023
Latest Amendment Date:	July 12, 2023
Award Number:	2308646
Award Instrument:	Standard Grant
Program Manager:	Jennifer Wade jwade@nsf.gov  (703)292-4739 EAR  Division Of Earth Sciences GEO  Directorate for Geosciences
Start Date:	September 1, 2023
End Date:	August 31, 2026 (Estimated)
Total Intended Award Amount:	$308,691.00
Total Awarded Amount to Date:	$308,691.00
Funds Obligated to Date:	FY 2023 = $308,691.00
History of Investigator:	Jessica Larsen (Principal Investigator) jflarsen@alaska.edu
Recipient Sponsored Research Office:	University of Alaska Fairbanks Campus 2145 N TANANA LOOP FAIRBANKS AK  US  99775-0001 (907)474-7301
Sponsor Congressional District:	00
Primary Place of Performance:	University of Alaska Fairbanks Campus 2145 N. TANANA LOOP FAIRBANKS AK  US  99775-0001
Primary Place of Performance Congressional District:	00
Unique Entity Identifier (UEI):	FDLEQSJ8FF63
Parent UEI:
NSF Program(s):	EPSCoR Co-Funding, Petrology and Geochemistry
Primary Program Source:	01002324DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):	9150
Program Element Code(s):	915000, 157300
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.050, 47.083

ABSTRACT

Volcanoes that produce explosive eruptions are very hazardous because they can create widespread ash clouds that are risky for aviation and cause damaging ash fall downwind. The White River ash (WRA) dacite tephra beds found in eastern Alaska and western Canada resulted from three of the most explosive eruptions (VEI 6) from a North American volcano, Mt Churchill, in the past ~2000 years. Those eruptions harmed the indigenous Dene people living in the areas downwind in present day Canada, resulting in a southward migration out of the impacted area. The current global reach of air traffic and the increased human population in downwind regions today mean that a similar-sized eruption from Mt Churchill could potentially cause catastrophic economic and human impacts. Despite its potential hazards, little is known about the source of its explosive, silicic magmas. This study will help us better understand where the magmas that feed Mt Churchill?s eruptions are stored in the crust. Although this volcano does not have a dedicated seismic monitoring network, knowledge of where the magmas live beneath the volcano can help us better estimate what might happen if the volcano becomes restless again in the future. Students will take part in this research during two summer courses taught by the PI at UAF. These courses will involve field trips to learn about the WRA deposits in eastern Alaska, collect samples, and then students will learn how to conduct experiments in the lab. The support from this grant will help cover student fees and field trip costs to encourage broad participation of students from historically excluded groups to help increase diversity in the geosciences. As a member of the Alaska Volcano Observatory, the PI will work closely with AVO colleagues to incorporate the results from this work into AVO operations and outreach efforts.

This study will use high pressure and temperature experiments to create a magma plumbing system model for the WRA eruptions. The team will build on petrological data from prior studies, which include mineralogy, temperature, and oxygen fugacity estimates needed for the experiments. They will use plagioclase-hosted melt inclusions to estimate entrapment pressures and volatile compositions by micro-FTIR analyses of H2O and CO2 (if present) and electron microprobe analyses of S and Cl. If reacted amphiboles are found, textural analysis will enable the team to estimate magma ascent rates using prior experimental calibrations. The petrology of the WRA tephra is well-suited for phase equilibria experiments, and the relatively low temperature range constrained by prior work allows for experimental methods that are suitable for student work and have a relatively low failure rate. The experiments will contribute to a magma plumbing system model for the WRA eruptions from Mt Churchill. These results will also be provided to researchers maintaining thermodynamical models to help augment their empirical datasets for increased accuracy applied to plagioclase and amphibole-bearing dacite to rhyolite magmas.

This project is jointly funded by Petrology & Geochemistry and the Established Program to Stimulate Competitive Research (EPSCoR).

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.

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