Collaborative Research: Phenocryst or not? Using a stratovolcano's crystal cargo to explore crustal-scale magmatic systems, Koma Kulshan (Mt. Baker), Northern Cascade Arc

Central Washington University, Ellensburg WA

Investigators

Abstract

The goal of this proposal is to address fundamental questions in volcano science related to how and when volcanoes erupt through a geochemical and mineralogical study of lavas erupted from Koma Kulshan (Mt. Baker) in northern Washington State. The United States has several volcanically active regions that contain “very-high-threat” volcanoes, including Koma Kulshan. While situated in a highly populated area, Koma Kulshan remains relatively understudied. This proposal investigates the processes that lead to eruptions at Koma Kulshan and the associated timescales, to better inform a response to, and aid in, hazard mitigation plans in the event of a future eruption. This work will also provide place-based learning opportunities for students from marginalized groups in STEM through the Summer Koma Kulshan Field Experience, a week-long summer field experience for pre-majors from Washington State institutions including Northwest Indian College, Whatcom Community College, and Yakima Valley College. Additionally, three PIs with complementary scientific expertise and diverse identities at different career stages will lead this collaborative project and will provide a framework for multi-tiered research mentoring across peer institutions in the state of Washington for undergraduates and graduate students. This proposal outlines an investigation of lavas and tephra deposits erupted from Koma Kulshan over the past ~100 ka. It provides an integrated approach combining proven petrologic techniques (i.e., mineral chemistry and textures and thermobarometry) with methodologies that are breaking new ground (i.e., machine learning, diffusion chronometry, and reconstructed volatiles in melt inclusions). The resultant data will be used to reconstruct the architecture of magma storage in arc crust and quantify the timing of magma storage and ascent prior to eruption–key factors required for eruption event trees and hazard mitigation plans implemented by the Cascades Volcano Observatory. Kulshan lavas provide a unique sample set ideal for this study as previous work has identified distinct crystal clots and co-crystallizing assemblages that represent different parts of a transcrustal system tapped upon eruption over 10s of thousands of years. This work provides the opportunity to test how transcrustal magmatic systems evolve through time and improves our understanding of arc volcanoes globally. 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.