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Full-Text Articles in Physical Sciences and Mathematics

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 Oct 2023

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 …


Using Two Coeval Andesites From Middle Sister And South Sister, Oregon, As Clues To Understanding Connectivity Between Adjacent, Coincident Stratovolcanoes, James Peale Jun 2023

Using Two Coeval Andesites From Middle Sister And South Sister, Oregon, As Clues To Understanding Connectivity Between Adjacent, Coincident Stratovolcanoes, James Peale

Geology Graduate and Undergraduate Student Scholarship

The Three Sisters Volcanic Complex in central Oregon is a cluster of three primary stratovolcanoes and a mafic periphery which lies at the intersection of the Cascade volcanic arc and the Basin and Range extensional province. This project focuses on the two youngest stratovolcanoes, Middle Sister and South Sister. Middle Sister experienced a period of frequent eruptive activity from approximately 27 ka to 14 ka, during which it erupted dacites, andesites, and basaltic andesites. South Sister experienced an intense period of eruptive activity from approximately 36 ka to 22 ka, during which it erupted a diverse suite of magmas ranging …


Understanding Potential Reservoir Interconnectivity Between Two Contemporaneous Volcanoes During The Onset Of Cone-Building Activity, Middle Sister And South Sister, Central Oregon, Emma Calvert Jun 2023

Understanding Potential Reservoir Interconnectivity Between Two Contemporaneous Volcanoes During The Onset Of Cone-Building Activity, Middle Sister And South Sister, Central Oregon, Emma Calvert

Geology Graduate and Undergraduate Student Scholarship

Klah Klanee (Three Points) is located in the central Cascades near Bend, Oregon. The Three Sisters Volcanic Complex (TSVC) lies at a tectonically complex intersection of the Cascade Subduction Zone, the Basin and Range Province, and the High Lava Plains. The TSVC is a compositionally diverse volcanic field consisting of four stratovolcanoes and numerous periphery cones and vents. Middle Sister and South Sister are the youngest of the stratovolcanoes and they share a largely contemporaneous and semi-alternating episodic eruptive history. These parallel histories could indicate a complex, interconnected magmatic root system within the crust below the TSVC and the surrounding …


Magnetic Methods To Characterize The Emplacement Of The Nodule Point Intrusion (Marrowstone Island, Wa), Charlie Nuncio Oct 2022

Magnetic Methods To Characterize The Emplacement Of The Nodule Point Intrusion (Marrowstone Island, Wa), Charlie Nuncio

Geology Graduate and Undergraduate Student Scholarship

The mafic intrusion of Nodule Point, Marrowstone Island, WA has sparse scientific literature to substantiate the local geologic history around its emplacement conditions. To fill this gap, rock magnetism and paleomagnetic methods have been applied to the intrusion and the sandstone of Scow Bay host rock. Samples taken from both lithologies were subject to thermal and alternating field demagnetization to assess paleomagnetic components. The Anisotropy of Magnetic Susceptibility (AMS) of samples was measured, and the maximum axis of susceptibility, K1, was used as an analog to hypothesize emplacement conditions. The host rock: the sandstone of Scow Bay, returned magnetization characteristics …


Populations Of Major Phases In Glacier Peak Lavas, Charlotte Wall Jan 2021

Populations Of Major Phases In Glacier Peak Lavas, Charlotte Wall

Geology Graduate and Undergraduate Student Scholarship

Volcanoes can be studied through minerals that are present in their eruption products. These minerals can be studied through optical microscopy and geochemistry to better understand their origins and provide insight into which processes took place prior to eruption (i.e., fractionation of crystals, assimilation of the surrounding crust, magma mixing). In this study I examine mineral populations in dacite (lava of intermediate composition) from Dahkobed/Glacier Peak volcano in the north Cascade Arc. The samples consist of a felsic (high SiO2) host component and a mafic (low SiO2) inclusion component. To establish base mineral populations, minerals from both the host and …


Chemical And Morphological Variance In Vitriclastic Shards From Iodp Site U1437: Inferences About Source Regions And Eruptive Mechanisms, Larissa Sleeper Dec 2018

Chemical And Morphological Variance In Vitriclastic Shards From Iodp Site U1437: Inferences About Source Regions And Eruptive Mechanisms, Larissa Sleeper

Geology Graduate and Undergraduate Student Scholarship

International Ocean Discovery Program (IODP) Expedition 350 recovered roughly 2000 meters of volcaniclastic material. This paper focuses on the first 100 meters of this core which was almost entirely composed of tuffaceous mud. Tiny (micron) vitriclastic shards within this mud were analyzed to determine their chemistry and their morphology to make inferences about their source environment and eruptive mechanisms.


Using Clinopyroxene Mineral Chemistry To Decipher Magma Composition Changes Over The 13 Million Year History Of The Izu-Bonin Volcanic Arc, Erin Benson Jun 2016

Using Clinopyroxene Mineral Chemistry To Decipher Magma Composition Changes Over The 13 Million Year History Of The Izu-Bonin Volcanic Arc, Erin Benson

Geology Graduate and Undergraduate Student Scholarship

International Ocean Discovery Program Expedition 350 recovered 2000 meters of volcanic rock core in spring, 2014 at the Izu-Bonin-Mariana Rear Arc. The core has been divided into seven lithostratigraphic units, from age 0 at the top to at least 13 million years at the bottom. The major and trace element geochemistry of representative mineral grains in volcaniclastic rocks throughout the core from top to bottom were analyzed and used as a proxy for interpreting magma compositional changes through time. The clinopyroxene from all units and the glass from Unit I were analyzed for major elements (by SEM and electron microprobe) …


An Introduction To Using Modflow The Usgs Modular Finite-Difference Ground-Water Computer Modeling System, Jessica N. Pfundt Jul 1995

An Introduction To Using Modflow The Usgs Modular Finite-Difference Ground-Water Computer Modeling System, Jessica N. Pfundt

Geology Graduate and Undergraduate Student Scholarship

MODFLOW is the U.S. Geological Survey (U.S.G.S.) Modular Finite-Difference Ground-Water computer modeling system. This program incorporates basic concepts derived from previous computer groundwater modeling programs. MODFLOW improves upon these programs because it is easy to modify, simple to use and maintain, can be executed on a variety of computers with minimal changes, and is relatively efficient with respect to computer memory and execution time (McDonald and Harbaugh, 1988).