Physical Sciences and Mathematics Commons^™

Deglacial And Holocene Environmental Change Recorded In Lake Sediments From The Snowy Mountains, Kosciuszko National Park, Southeastern Australia, Emma J. Mickelson

WWU Graduate School Collection

The sediment record from Lake Albina, the Snowy Mountains, southeastern Australia suggests significant environmental change mostly reflecting shifts in climate from the LGM through the Holocene. Immediately following deglaciation, approximately 19.4 thousand cal ky BP, Lake Albina experienced cold and/or dry conditions with minimal vegetation in the catchment. Cooler conditions persisted with a slight increase in moisture throughout the Antarctic Cold Reversal (ACR; 14.7-13 cal ky BP) aligning closest with a strengthening of the Atlantic Meridional overturning circulation (AMOC) and a northward shift of the South Westerly Winds (SWW). Between 12.9-9.7 cal ky BP, Lake Albina recorded a climate reversal …

Modeling 21st Century Peak Flows In The Nooksack River Basin In Northwestern Washington State Using Dynamically-Downscaled Global Climate Model Projections, Evan A. Paul

WWU Graduate School Collection

The Nooksack River in northwestern Washington State provides freshwater for agriculture, municipal, and industrial use and serves as a vital habitat for endangered salmon, a resource that is of cultural and economic importance to the Nooksack Indian Tribe and the surrounding region. As more landscape becomes exposed to rain rather than snow and heavy winter precipitation events intensify (i.e., atmospheric rivers), peak flows and sediment delivery to streams will increase due to rapid runoff, resulting in salmon habitat degradation and increased flood risk. Thus, anticipating the effect of climate change on peak flows is crucial for salmon habitat restoration efforts …

Connections Between Eruption Style And Magmatic Reservoir Evolution: Insights From Augustine Volcano, Alaska, Usa, Mahinaokalani G. Robbins

WWU Graduate School Collection

At a single volcano, eruptive behavior can change through time as the plumbing system evolves. Augustine Volcano, a frequently active intermediate stratovolcano in the Alaska-Aleutian arc (USA), is an ideal setting to investigate magma reservoir processes due to its frequent modern and Holocene eruption history. Its most recent 2006 CE eruption included mixed effusive and moderately explosive (VEI 3) events and has been studied in detail. Proximal fall deposits from this eruption were generally mixed fine ash to lapilli with variable thickness, but typically ~5 cm on the island (Wallace et al., 2010). The Pre-contact “Tephra M” was deposited by …

A Mixed-Methods Study Of Geoscience Identity, Race/Ethnicity, And Gender In Senior Undergraduate Geoscience Majors, Willa Rowan

WWU Graduate School Collection

I conducted a mixed methods study of geoscience identity in undergraduate students to examine the cultural and social aspects of geoscience degree programs. White students are overrepresented in geoscience, and a priority of anti-racism efforts in the field is listening to the experiences of students who are Black, Indigenous, or people of color (BIPOC) to better inform equity and inclusion goals. Structural racism in geoscience pushes BIPOC students out of the field, and it can be better understood by studying socially constructed aspects of learning such as geoscience identity. This study is the first to measure geoscience identity with a …

Using Camera-Monitored Sediment Traps To Evaluate Sediment Availability And The Role Of Waves In Resuspending Seafloor Sediment, Bellingham Bay, Wa, Liam Horner

WWU Graduate School Collection

Understanding nearshore sediment budgets and processes is important for evaluating coastal hazards, habitats, and contaminant fate to enable informed decisions in coastal planning and management. I aimed to evaluate the role of waves in resuspending and redistributing sediments and by proxy contaminants in the urban/estuarine Bellingham Bay, and better understand the transport and rate of fluvial sediment moving through the nearshore. I integrated analyses using camera-mounted sediment traps, seafloor grain-size data, short-lived radioisotopes, and other fluvial, physical oceanographic, and wind data. I paired cameras with sediment traps, to identify the timing and rate of sedimentation on the seafloor at hourly …

Biomarker Study Of Bellingham Bay : Identifying How Urbanization Has Affected Carbon Storage And Eelgrass, Jess Shulman

WWU Graduate School Collection

Understanding sediment sources and fluxes throughout coastal zones is essential to evaluate shoreline stability, ecosystem health, and the potential for carbon storage. In Bellingham Bay, WA, like many developed coastal settings, urban areas have replaced forested cover and altered sediment fluxes, yet little is known of their offshore impacts. I analyzed n-alkanes, found in plant leaf waxes preserved in marine sediments of Bellingham Bay to characterize sediment sources and reconstruct changes in the relative contributions of eelgrass beds to sedimentary organic matter since pre-industrial times using a linear mixing model. Eight 2-meter-long cores were analyzed in order to determine how …

Reconstructing Wildfire Regime During The Warm Paleocene-Eocene Climate Using Molecular Biomarkers From The Chuckanut Formation In Northwest Washington, U.S.A., Alexandra Thompson

WWU Graduate School Collection

Wildfires are expected to increase in frequency and severity as climate changes in the Pacific Northwest of North America. To better understand the effect of warming climate on wildfire regimes, I present the first reconstruction of past wildfire frequency and severity during the Paleocene-Eocene transition in northwest Washington state, U.S.A. The Chuckanut Formation is a late Paleocene to Eocene sedimentary unit with a robust paleobotanical record showing the existence of subtropical forests in northwest Washington during the Paleocene, transitioning to a relatively cooler Eocene, dominated by temperate mixed forests. Geochemical records of environmental change coinciding with Paleocene-Eocene climatic change in …

Using Chemical Zoning In Minerals To Understand Magmatic Processes At Augustine Volcano, Alaska, Sloane Kennedy

WWU Graduate School Collection

The eruption behavior of a volcano is intrinsically linked to magmatic evolution. Augustine Volcano is an active stratovolcano in the Aleutian Arc (AK, USA), showing stratigraphic evidence that eruptions before 1,800 C.E. were more explosive, producing thick pumice deposits, compared to the six eruptions observed in the last 200 years. Tephra B, an understudied ~400-year-old pumice fall unit, represents the last more explosive style eruption at Augustine - making it ideal for studying how changes in magmatic evolution can result in changes in eruption style. For this thesis, I used textural zoning patterns and chemical variations (major and trace elements) …

U-Pb Zircon Geochronology And Structure Of Regional Blueschist Units In The Easton Metamorphic Suite, Northwest Cascades, Wa, Katherine Lang

WWU Graduate School Collection

The Easton metamorphic suite of the Northwest Cascades Thrust System (NWCS) is a well-preserved subduction accretion complex in Washington State. The regional blueschist units of the Easton metamorphic suite include the Mt. Josephine semi-schist, Darrington Phyllite, and Shuksan greenschist/blueschist and all are interpreted to have accreted after the onset of Jurassic subduction beneath North America. This study uses zircon U-Pb geochronology, structure, and field observations to test the regional correlations between units in the Easton metamorphic suite and address models for the timing of subduction accretion along the North American margin in the Late Jurassic – Early Cretaceous. The results …

Investigating Kīlauea’S 2018 Offshore Lava Emplacement Through Hydroacoustic Data, Olana Costa

WWU Graduate School Collection

The 2018 eruption of Kīlauea Volcano produced an unprecedented volume of lava, creating 3.5 km² of new land on Hawai`i’s Big Island (Soule et al., 2021). Lava expelled from the Ahu`aila`au vent (originally called Fissure 8) traveled ~13 km to where it entered the ocean. Over half of the lava erupted in 2018 was emplaced offshore where it produced four new submarine lava deltas (Soule et al., 2021). In response to the eruption, a network of 12 ocean-bottom seismometers (OBS) with attached hydrophones was deployed on Kīlauea’s submarine south flank. Ten of the instruments successfully recorded data from July …

Does Sediment Supply Impact The Threshold For Initial Sediment Motion In Natural, Gravel Bedded Streams?, Emily Loucks

WWU Graduate School Collection

Sediment transport in river channels control channel morphology, streamflow, and benthic ecosystems. Predicting sediment transport rates through a channel is required for sediment management for stream restoration and aquatic habitat assessment. The critical Shields stress (τ*_c), is a dimensionless parameter used in sediment transport models that characterizes the river bed surface shear stress required to initiate sediment motion. The τ*_c is typically assumed constant in transport models, yet compilations of field data have shown that τ*_c can vary wildly, causing sediment transport models to over- or under-predict fluxes by an order of magnitude or more. Understanding …

Paleomagnetic Determination Of Vertical Axis Block Rotation Near The Doty Fault In Southwestern Washington, Charles Linneman

WWU Graduate School Collection

In this paper I present the results of paleomagnetically derived vertical axis rotations (VARs) of sites in two different flows of the Columbia River Basalt (CRB) – the 16 Ma Sentinel Bluffs member of the Grande Ronde flow and the 12 Ma Pomona Member of the Packsack Lookout – near the Doty fault in southwestern Washington. In two field seasons, I collected 99 cores from 14 sites, 11 in the Grande Ronde flow and three in the Pomona member flow. Of the 227 specimens that I demagnetized, 212 had well-defined magnetic directions. Positive fold and reversal tests results confirm the …

Quantifying Channel Change Following Post-Fire Debris Flows In A Steep, Coastal Stream, Big Sur, California, Telemak Olsen

WWU Graduate School Collection

Debris flows commonly occur following wildfire in steep landscapes, introducing large volumes of sediment to downstream fluvial systems. Fire-related sediment supply perturbations impact channel morphology, and importantly, fragile aquatic and riparian ecosystems downstream of disturbance. The Big Creek watershed drains 57 km² of steep chaparral and coast redwood forest along California’s Central Coast. Streams in the Big Creek watershed typically exhibit step-pool/cascade morphology and serve as vital spawning habitat for anadromous Steelhead Trout (Oncorhynchus mykiss). In 2020, 97% of the Big Creek watershed burned in the Dolan Wildfire. In January 2021, an atmospheric river event triggered a series of …

Modeling The Effects Of Projected Climate Warming On Stream Temperatures In The Stillaguamish River Basin, Emily E. Smoot

WWU Graduate School Collection

The Stillaguamish River is a snow-and-rain mixed basin and the fifth largest river in the Puget Sound basin. Elevations in the 1700 km² Stillaguamish River basin reach roughly 2000 m and historically a snowpack is sustained above 1000 m. Snowmelt in the basin is important for sustaining spring and summer streamflow and buffering stream temperatures. Stream temperature increases are of significant concern because of the threatened Chinook salmon (Oncorhynchus tshawytscha) population.

I reexamined projected stream temperatures in the Stillaguamish River by forcing the coupled Distributed Hydrology Soil Vegetation Model and River Basin Model with dynamically downscaled meteorological …

To Erupt Or Not To Erupt? That Is The Question: Extremely High Levels Of Background Seismicity And Lack Of Eruptivity From 2003-2019 At Gareloi Volcano, Aleutian Islands, Alaska, Kiana Tamarie Harris

WWU Graduate School Collection

Mount Gareloi, one of the westernmost volcanoes in the Aleutian arc, has not erupted since 1989, yet it continuously exhibits extremely high levels of background seismicity. Hundreds of volcanic earthquakes are recorded per day on the island since seismometer installation in 2003. I analyzed and classified seismic data collected from 2003-2019 to explore the geophysical processes causing this consistent seismicity with no subsequent eruptive activity. Analysis of waveform and corresponding spectra indicate the vast majority of Gareloi earthquakes are characterized by frequencies between 1 and 5 Hz, which are typical of long-period (LP) events, and these events are particularly dominant …

Cycles Or Repetitions: A Quantitative Analysis Of Alluvial Bed Thicknesses, Kristopher D. Phillips

WWU Graduate School Collection

Sedimentary strata display a range of repetitive patterns from interbedded lithofacies through recurring sequence stratigraphic systems tracts. Highly structured, large-scale patterns are commonly ascribed to cyclic allogenic forcings such as eustasy and climate. In contrast, autogenic processes are typically thought to impart stochastic noise or limited small-scale structure on stratigraphy. Recent studies indicate some autogenic processes in fluvial and fluvio-deltaic systems such as the large-scale compensational deposition (i.e., the tendency for a channel to occupy and fill topographic lows in a basin), can occur on spatiotemporal scales that may overlap with some allogenic forcings. These autogenic processes could impart deterministic, …

Structural History Of The Formidable-Le Conte Mountain Area, North Cascades, Wa, Nyle Weldon

WWU Graduate School Collection

A record of Permian to Tertiary polyphase deformation, metamorphism and magmatism is preserved in the Cascades River region of the North Cascades Crystalline Core, Washington. The tectonic history recorded here can be used to understand the deep crustal processes occurring within active convergent plate margins around the world. New structural and geochronologic data from this study are used to advance our understanding of terrane origin, accretion, and processes that altered and thickened the crust of the North Cascades.

The study focuses on several rock units within an accreted Permian-Jurassic island arc, the Chelan Mountains terrane, that was tectonized in Cretaceous …

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 …

Reconstructing Deglacial And Holocene Climatic And Environmental Change In The Snowy Mountains Of Southeast Australia, Aidan Warner Burdick

WWU Graduate School Collection

Multi-proxy, long-term records of deglacial and Holocene climatic and environmental change in southeast Australia are rare, leaving the region a gap in local and large-scale synoptic climate reconstructions. The Snowy Mountains include the highest and coldest regions of mainland Australia and were the only part of the mainland that was glaciated during the late Pleistocene. Lakes formed by the glaciers have provided continuous sediment traps since glacial retreat following the Last Glacial Maximum. In this report, I reconstruct the maximum ice extents of glaciers during the last glacial period and estimate their equilibrium line altitudes, revising the work of Barrows …

Forearc Erosion In Response To Megathrust Plate Coupling Along The Wairarapa Coastline, New Zealand, Chantel E. Jensen

WWU Graduate School Collection

How the subduction zone earthquake cycle contributes to uplift, erosion, and permanent deformation of the overlying forearc remains largely unknown. The Hikurangi subduction zone (HSZ), along the east coast of the North Island of New Zealand, provides a unique location to examine the effects of subduction coupling on forearc deformation over multiple millennia. There, the Wairarapa coastline runs parallel to the HSZ and spans a transitional boundary between locked and freely slipping portions of the plate interface. Using digital topographic analysis and catchment-averaged erosion rates from ¹⁰Be in fluvial sands, I examined the geomorphology of the HSZ forearc to …

Testing Potential Triggering Mechanisms Of Long-Runout Catastrophic Rock Avalanches In The Nooksack River Basin, Whatcom County, Washington, Eric R. Brown

WWU Graduate School Collection

The Nooksack basin contains five large Holocene long-runout rock avalanche deposits. Similarities and spatial proximity of the deposits suggest that they may share a common triggering mechanism. Two of the deposits, Van Zandt Landslide Complex (VZLC) and Church Mountain Sturzstrom (CMS) have published ages that overlap with prehistoric earthquakes, suggesting seismicity may be the cause. To further test this idea, I mapped and dated the remaining three deposits, Racehorse Creek (RHC), Middle Fork (MFN), and Maple Falls (MF). To establish ages for the slides, I combined radiocarbon dating of organics in sediment cores from bogs in the debris fields and …

Spectral Variability In Naturally Weathered Rock Surfaces And Implications For Mars, Sabrina Curtis

WWU Graduate School Collection

Rock weathering products are important clues for understanding past environmental conditions on Mars. They can be identified using reflectance spectroscopy because the formation of new minerals and textures on a rock surface will change its spectral signature. Previous studies demonstrate that the spectral signature of coated rock surfaces can vary with viewing geometry (the angle between incident and emitted light); however, these photometric effects have not been extensively characterized for naturally weathered rocks. My goal in this study is to quantify how both weathering and viewing geometry affect visible to near-infrared (VNIR) reflectance spectra of a subset of naturally weathered …

Eruption Evolution Of West Mata Volcano, Ne Lau Basin Using Hydroacoustic And Video Data, Mikkel Shanice Louis

WWU Graduate School Collection

West Mata Volcano located in the NE Lau Basin is the site of the deepest observed submarine volcanic eruption, 1,200 meters below sea level. In May 2009, a research cruise collected video data of two eruptive vents showcasing different eruption styles. During the same research cruise, a Bprobe^TM portable hydrophone was deployed at the summit of West Mata and collected data that coincides with video recorded at the vents during ROV dives. These data sets were correlated to better understand the spectral signatures associated with the two eruptive vents. Both vents were near the summit, about 50 meters apart, …

Structural History Of The Bald Mountain Mining District, Nevada, Usa, David Paul Ryan

WWU Graduate School Collection

The Bald Mountain Mining district, like much of central Nevada, has experienced a complex deformation history. The mining district is considered here as a southern extension of the well-studied Carlin trend of gold deposits to the north. In order to gain a better understanding of how the Bald Mountain Mining District structural style relates to other structural models developed to the north in the Carlin trend, I completed a mapping and structural domain analysis in the district, with a focus on the North Mooney basin area where a high spatial concentration of Carlin-type gold deposits occur. The identification of structural …

Modeling 21st Century Peak Streamflows In The Stillaguamish Watershed Using Dynamically Downscaled General Circulation Model Projections, James Marcell Robinson

WWU Graduate School Collection

Climate change is projected to increase river flooding in the Puget Sound region of Washington State by reducing snowpack and yielding more intense storm events. Pairing meteorological forcings from general circulation models (GCMs) with a physically based hydrologic model is a robust method of assessing watershed response to projected climate. Before GCM forcings can be applied to regional hydrologic models, some form of downscaling or regionalization is required. Dynamical downscaling is a means of incorporating mesoscale atmospheric processes within GCM-informed boundary conditions. Here I apply climate projections, dynamically downscaled using the Weather Research and Forecasting model (WRF), to the Stillaguamish …

A Mastcam Multispectral Investigation Of Rock Variability In Gale Crater, Mars: Implications For Alteration In The Clay-Sulfate Transition Of Mount Sharp, Alivia Eng

WWU Graduate School Collection

The Mars Science Laboratory Curiosity rover has explored over 650 m of strata since landing in 2012. After leaving Vera Rubin Ridge (VRR), the rover traversed though the phyllosilicate-rich region, Glen Torridon, and the Mg-sulfate-bearing strata that lies above it, with excursions onto the Greenheugh Pediment and Amapari Marker Band. These unique stratigraphic units were investigated using Curiosity's instrument suite which includes the Mast Camera (Mastcam) pair of multispectral imagers. Mastcam’s narrowband filters are sensitive to iron-bearing phases and some hydrated minerals. We used Mastcam spectra, in combination with chemical data from Curiosity’s CheMin, APXS and ChemCam instruments, to assess …

Glacier Peak And The Chocolate Factory: Recurring Debris Flows From The Eastern Flank Of Glacier Peak Stratovolcano, North Cascades, Washington State, Usa, Edward M. Fordham

WWU Graduate School Collection

Alpine mass wasting events can have wide ranging impacts that extend past their headwater origins reaching down to lowland population centers. The Suiattle River, which drains the eastern flank of Glacier Peak in the North Cascades of Washington State, is a dominant contributor of suspended sediment in the region. Normalized for drainage area, the Suiattle River supplies more suspended sediment than nearly any other river in the region and more than twice as much as the White Chuck River, which drains the western flank of the volcano. Despite its known importance to the regional sediment budget, the specific geomorphic drivers …

Martian Spectroscopy: Laboratory Calibration Of The Perseverance Rover’S Mastcam-Z And Photometric Investigation Of Mars-Analog Ferric-Coated Sand, Kristiana Lapo

WWU Graduate School Collection

The Mars 2020 rover Perseverance will search for signs of past habitability and biosignatures after landing in Jezero Crater in February 2021. Spectroscopy is a vital tool for planetary remote sensing and Perseverance is equipped with Mastcam-Z, a stereoscopic, zoom-enabled, multispectral imager that can acquire true color images with red, green, and blue (RGB) color filters, and visible- to near-infrared images with 12 narrowband science filters between 400 and 1100 nm. Mastcam-Z will provide operational support for the rover as well as directly contribute to Perseverance’s geologic investigations. Given the integral role of Mastcam-Z in the Mars 2020 mission, calibration …

Marine Ecosystem Response To Late Pleistocene Rapid Climate Change In The Salish Sea, Alex Victor Hernandez

WWU Graduate School Collection

The ecologic response of marine invertebrates during collapse of the Cordilleran Ice-sheet through the Late Pleistocene has been insufficiently studied across the lowlands of northwestern Washington State and southern Fraser Valley, British Columbia. Assessment of the response of these nearshore marine assemblages to climatic shifts will improve our understanding of closely related modern taxa in analogous climate-stressed conditions. If we understand the former vulnerability of related genera, meaningful predictions may thus be provided for extant taxa in current and future time. In this thesis, I establish a compilation dataset of all relevant specimens collected within the Salish Sea and Puget …

Revaluating The Use Of Mollusks For Estimating Paleodepth In The Pacific Northwest, E Worthington

WWU Graduate School Collection

Fossil records have the potential to extract important paleoenvironmental records, and by ground truthing our assumptions with modern mollusks we can improve our interpretations of the fossil record. Modern molluscan death assemblages from Rosario Strait were analyzed to: 1) determine to what extent the molluscan communities were controlled by grain size or depth; and 2) determine the extent to which age mixing was occurring in the death assemblage. Twenty-eight Van Veen grab samples were collected in Rosario Strait to represent range of depth and grain sizes. All samples were wet sieved to isolate mature mollusks (> 2.00 mm), and sediment …