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The Goat Rocks Volcanic Complex is an extinct cluster of major stratovolcanoes in the Cascade Arc. Due to glaciation, the full life cycle of the Goat Rocks is exposed providing a rare window into how a Cascade volcano is born, evolves, and dies. Ongoing research includes characterizing the relationship between pre-existing crustal rocks and magmatic processes, specifically testing petrologic models such as crustal assimilation and recharge as well as comparing an extinct system to active Cascade systems. This work is a collaboration with Dr. Kellie Wall of USGS-Cascades Volcano Observatory.
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A view from Hogback Mountain, a peripheral mafic shield volcano in the Goat Rocks area (Photo credit: K. Wall)
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Koma Kulshan (Mt. Baker) is a volcano in northern Washington that is nestled in the highly populated area of Bellingham. While Kulshan is classified as a very high-threat volcano (USGS), the pre-eruptive history of the magmas through time remain unclear. Our team is combining mineral chemistry, diffusion chronometry, and petrologic modeling to help determine the storage conditions and pre-eruptive history of Baker magmas. This work is a collaboration with Prof. Sue DeBari at WWU and Asst. Prof. Kristina Walowski at WWU. This work provides the opportunity to understand how transcrustal magmatic systems evolve through time and improves our understanding of arc volcanoes globally.
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Kulshan collaborators standing at Artists Point, WA
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Emily Yoder presenting her research findings on Mt. Baker at GSA 2024 Spokane
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Desiree` Cunningham presenting her research findings on Mt. Baker at GSA 2024 Spokane
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Banded pumices are common in ignimbrites, and intricate layering indicates that they form during magma ascent. Based on this assumption we used electron microprobe analytical transects of contacts between dark and light, glassy high-silica rhyolite layers in pumices from the Rattlesnake Tuff to infer magma ascent rates through diffusion chronometry. Modeling indicates maximum time scales between mingling and conduit ascent from minutes to hours. Viscosity calculations for each rhyolite composition suggest that highly viscous rhyolites have longer ascent times and than low-viscosity magmas.
Banded pumice samples from the Rattlesnake Tuff, part of the High Lava Plains in Eastern Oregon.
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Summary of calculated diffusion times for both Si and Ba. Diffusion times are grouped by the respective rhyolite mingling combination. Thick vertical lines are best-fit time, and shaded region surrounding each best-fit time is the associated error envelope. Viscosity contrast ratios are reported in parentheses (Shamloo & Grunder, 2023)
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Yellowstone is a well-known volcano due to its catastrophic history and present-day hydrothermal and seismic activity. Our research suggests eruption initiation by magmatic recharge can occur on the scale of a human life (weeks to decades at most) in the case of the Lava Creek Tuff Supereruption (Shamloo and Till 2019; Shamloo et al. 2021). This work received press coverage in the New York Times and is featured in National Geographic Documentary series.
Shamloo, H., Till C. B., Hervig, R. L., (2021) Multi-Mode Magnesium Diffusion in Sanidine: Applications for Geospeedometry in Magmatic Systems. Geochimica et Cosmochimica Acta. https://doi.org/10.1016/j.gca.2021.01.044
Shamloo H. I., Till., C.B., (2019) Decadal Transition from Quiescence to Supereruption: Petrologic Investigation fo the Lava Creek Tuff, Yellowstone Caldera, WY. Contributions to Mineralogy and Petrology, 174(4), 32. Till C.B., Vazquez J.A., Stelten M., Shamloo H. I., Shaffer J., (2019) Co-existing Discrete Bodies of Rhyolite and Punctuated Volcanism Characterize Yellowstone’s Post-Lava Creek Tuff Caldera Evolution. Geochemistry, Geophysics, Geosystems. |
Ash distribution of three Yellowstone supereruptions, the most recent of which covered the majority of the USA (USGS.gov).
Figure from Shamloo et al., (2021) showing diffusion profiles of Mg, Sr, and Ba in sanidine from Lava Creek Tuff supereruption.
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