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Full-Text Articles in Physical Sciences and Mathematics

The Past Is The Key To The Present: Reconstructing Changes In Seasonal Precipitation Triggered By Ancient Climate Change, William Ward May 2020

The Past Is The Key To The Present: Reconstructing Changes In Seasonal Precipitation Triggered By Ancient Climate Change, William Ward

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Plant biomarkers have grown in use for defining paleoclimates in the geologic record, especially during major climate change events. Research utilizing these biomarkers often looks at leaf waxes within preserved organic matter in the rock record. These waxes are resilient to decomposition and thus are invaluable to paleoclimate reconstruction. Specifically, changes in the composition of hydrogen isotopes (D/H) in leaf wax lipids (n-alkanes and fatty acids) reflect changes in precipitation and can be used to model variability in the hydrologic cycle during major climate change events, such as abrupt global warming events (e.g. hyperthermals). The Paleocene-Eocene Thermal Maximum (PETM), about …


Calibration Optimization Of A Stream Temperature Model Applied To The Nooksack River, Ian Edgar May 2020

Calibration Optimization Of A Stream Temperature Model Applied To The Nooksack River, Ian Edgar

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The River Basin Model (RBM) is used to assess how stream temperatures will change in the Nooksack River due to warming climates by tracking heat exchanges along stream segments. Before modeling forecasted climate scenarios, I first calibrated the model to observed historical stream temperatures. The calibration of the RBM to a stream network involves the adjustment of eleven different variables until the simulated temperatures match observed historical stream temperatures. Because the manual process of calibrating the model is extremely time consuming, I developed a Python script to converge on the optimal variables required for the RBM calibration. The script adjusts …


Recreating Intercalated Clays Of Chondritic Meteorites, Katherine Winchell May 2017

Recreating Intercalated Clays Of Chondritic Meteorites, Katherine Winchell

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In order to better understand the reactions that form intercalated clays in carbonaceous chondritic (CC) meteorites, a suite of six combinations of nontronite plus fine-grained metal, organics, or sulfur ± water were heated at a temperature of 200°C in sealed Parr bomb containers for a period of three months. Intercalation is the process of materials being introduced between the layers of expandable clays via cation exchange. Reflectance spectra of CC meteorites differ from those of mixtures of the end members made physically in that the CC spectra are darker and show extremely subdued absorption bands of the phyllosilicates (clays) that …


Analysis Of Concentric Growth Rings In Hydrothermal Epidote, Brandi Petryk May 2017

Analysis Of Concentric Growth Rings In Hydrothermal Epidote, Brandi Petryk

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Crystals found within geothermal cores from Akutan Island, Alaska, show concentric growth rings of what appear to be alternating bands of epidote and clinozoisite minerals. The intent of this project is to determine the nature of these growth rings and what processes could allow them to form. Our working hypothesis is that the rings are due to fluctuations in the oxidation states of the hydrothermal system, which would control the amount of available Fe3+ needed to make epidote. In relatively reducing conditions, Fe3+ would be scarce and clinozoisite (Fe-poor variety of epidote) would form. We have tested this hypothesis by …


Using Clinopyroxene Mineral Chemistry To Decipher Magma Composition Changes Over 13 Million Years In The Izu-Bonin Volcanic Arc, Erin Benson, Brian Rusk, Ricardo Escobar, Luan Heywood May 2016

Using Clinopyroxene Mineral Chemistry To Decipher Magma Composition Changes Over 13 Million Years In The Izu-Bonin Volcanic Arc, Erin Benson, Brian Rusk, Ricardo Escobar, Luan Heywood

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International Ocean Drilling Program (IODP) Expedition 350 drilled into the relatively unexplored rear arc of the Izu-Bonin-Mariana system (see map). It recovered 2000 meters of volcanic rock core in the spring of 2014. The core has been divided into seven lithostratigraphic units, from age 0 at the top to at least 13 million years at the bottom. I analyzed the major and trace element geochemistry of representative clinopyroxene and glass (in Unit I) and just clinopyroxene (in all other units) in volcaniclastic rocks throughout the core from top to bottom and used them as a proxy for interpreting magma compositional …


The Geomorphic Signature Of Fold Growth Along Cleman Mountain, Wa, Tabor Reedy May 2015

The Geomorphic Signature Of Fold Growth Along Cleman Mountain, Wa, Tabor Reedy

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No abstract provided.