Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Publication
- Publication Type
Articles 1 - 4 of 4
Full-Text Articles in Geology
Using Trace Element Concentrations In Volcanic Ash To Elucidate Magma Sources To Koma Kulshan’S (Mount Baker) Most Recent Explosive Eruption – The 6.7 Ka Ba (Black Ash) Tephra, Stone Machel
Geology Graduate and Undergraduate Student Scholarship
Koma Kulshan (Mount Baker) is an active stratovolcano in the northern Washington Cascades. Kulshan’s most recent magmatic eruption at 6.7 ka was explosive, producing the ~0.2 km3 BA tephra (black ash) from the edifice (Scott et al. 2019). Comprehensive geochemical data for the BA tephra were previously limited to major elements from one whole rock lapillus (silicic andesite) and several in situ glass analyses (dacite), despite being Kulshan’s most voluminous Holocene tephra. Here, I present the first extensive major and trace element study of the pyroxene- and plagioclase-bearing BA tephra glass to determine magma source and eruption processes. My …
Shared Roots: A Geochemical Investigation Of Basaltic Andesites To Understand Magmatic Cogenesis At The Middle Sister And South Sister Volcanoes, Central Oregon, Sean Francis Halstead
Shared Roots: A Geochemical Investigation Of Basaltic Andesites To Understand Magmatic Cogenesis At The Middle Sister And South Sister Volcanoes, Central Oregon, Sean Francis Halstead
WWU Honors College Senior Projects
The Middle Sister and South Sister volcanoes, near Bend, Oregon, are overlapping, active Cascade Arc stratovolcanoes which share a complex, contemporaneous eruptive history. This history is characterized by an extreme compositional diversity of lavas erupted in alternating phases of high activity from one neighboring volcano to the other, with both vents producing material ranging from basaltic andesite to rhyolite. This system is understood to be predominantly fed by basaltic andesites fractionated from partial mantle melts within the lower crust, but magma compositions are additionally impacted by mixing, assimilation, and crustal contamination while in transit to the surface. Thus, the subterranean …
Using Crystal Zoning, Thermobarometry, And Melts To Elucidate Koma Kulshan’S (Mt. Baker) Transcrustal Magma Storage System, Northern Cascade Arc, Brendan Garvey
Using Crystal Zoning, Thermobarometry, And Melts To Elucidate Koma Kulshan’S (Mt. Baker) Transcrustal Magma Storage System, Northern Cascade Arc, Brendan Garvey
WWU Graduate School Collection
Koma Kulshan (Mt. Baker) is classified as a high-threat volcano due to its past eruptive history and its proximity to populations, yet its eruptive products are understudied. Combining mineral chemistry from complexly zoned crystals with thermobarometry and thermodynamic modeling (MELTS) is a powerful way to provide constraints on magmatic processes beneath an active volcano. Up to four populations each of pyroxene, plagioclase, and olivine occur as phenocrysts and crystal clusters in the youngest (9.8 ka) lava flow at Koma Kulshan and represent four co-crystallizing assemblages derived from distinct magmas. These co-crystallizing assemblages are defined by petrologic observations and mineral chemistry …
Geochemistry Of The Mt. Persis Volcanics And Evidence For Thickening Of Cascade Crust Over Time, Monica Hanson
Geochemistry Of The Mt. Persis Volcanics And Evidence For Thickening Of Cascade Crust Over Time, Monica Hanson
Summer Research
The Cascade Range is a classic example of a continental magmatic arc, a belt of igneous activity resulting from subduction of the oceanic Juan de Fuca plate beneath the western margin of the North American plate. The Cascade arc, which started forming about 38 million years ago, is unique in that extensive uplift and erosion have exposed plutonic and volcanic rocks of similar age. This study will focus on the Mt. Persis area in the North Cascades, where a pluton of the Index batholith is surrounded by near-source volcanic rocks and suggests that the volcano may have originated from the …