Geosciences Capstones 2020
Exploring the topography of Mount Rainier and its impact on the transport of debris to the supraglacial system
In this study I will be looking at the effects of topography within a glacier’s rock-shed on the transport of debris from surrounding glacial features to the glacier surface. The glaciers targeted for this research were Emmons, Frying Pan, Nisqually, and South Tahoma Glaciers. Debris that gets transported to the glacier surface has the ability to impact and prolong the glaciers life (Pelto, 2000). It is important to understand this transport process so that we can gain a better understanding of a glaciers life span. In order to evaluate this I worked with a GIS program, ArcMap, that allowed me to create a slope and feature map. These maps allowed me to see the steepness of the topography in the rock-shed and the possible supplies of debris to the glacier surface. After this was done a scoring system was used to evaluate the overall likelihood of each glacier’s rock-shed to supply debris to the glacier surface (Saroglou, 2019). Steepness showed to have a moderate impact on the transportation of sediment to the glacier surface. The size of the rock-shed also didn’t show to impact the transportation of debris to the glacier surface.
Mesoproterozoic Rock Analysis in Northern Tusas Mountain Range, New Mexico
Continents are made by the extraction of new igneous materials from the mantle, recycling of existing sedimentary materials, and tectonic accretion and imbrication of these materials into new crustal segments. Understanding the tectonic processes that control how this happens requires seeing how the strongest part of the crust, which is in the middle, (~12-16 km down) evolved over time during assembly. Proterozoic rocks of Northern New Mexico in general provide an opportunity to study how continental crust develops from the important perspective of the middle crust. Mesoproterozoic rocks of the Tusas Mountains preserve a succession of geologic events that include the initial development of island arc rocks, deposition of sediments and intrusion of granites, and two to three significant episodes of deformation that have been interpreted to record the assembly of the crust in this region. Critically, the typical cross-cutting field relationships between the sediment and granites, and therefore assembly processing, are not clear. Assembly could have occurred very quickly, in ~20 Ma, or may have taken up to ~250 Ma.
The Timing of Deglaciation in Alaska Since the Last Glacial Maximum
Glaciers globally have been in retreat since the Last Glacial Maximum, and the timing of deglaciation in Alaska has not yet been fully understood. Surface exposure studies have been done in Alaska to understand the history of the glaciation. It was expected that glaciers at lower latitudes would have deglaciated first. Surface exposure ages from previous studies throughout the state were spatially compared to determine the timing of deglaciation. Results show higher latitude regions of Alaska deglaciating ~20 ka, and lower regions ~17 ka with fluctuations of advancing and retreat in the southern regions. Glaciers in Alaska were likely responding to changes in atmospheric circulation due to other continental ice sheets receding. The timing of deglaciation in Alaska was different throughout the state with each region deglaciating at different times.
The Impact of Urbanization on Streamflow in the Puget Lowland Region
This study is about the effect of urbanization on streamflow, specifically in the Pacific Northwest, and how different degrees of urbanization produces different flow rates. This was a synthesis project, finding gauge data about the basins and analyzing it. Two basins were chosen from King County and one from Snohomish County based on their percent impervious surface and other characteristics such as size, shape, etc. Streamflow data from the past ten years was gathered for each basin and used to produce graphs. The data show that overall, the second most urban basin has higher flow rates but the most urban basin has the lowest flow rates. This is explained by the restoration work that the most urban basin has undergone to prevent further flooding. As urbanization continues to increase, the discharge rates in streams will also increase unless restoration work similar to what the most urban basin has had done is applied to other basins.
Geologically Controlled Contaminate Flow at the Hanford Nuclear Site
The Hanford Site, established in 1943 and now decommissioned, was a nuclear weapons production site created as part of the Manhattan Project in Benton County, Washington on the Columbia River (DOE 1). Decades of manufacturing at the site has left millions of gallons of contaminants behind, which have seeped into the ground and are slowly leaching into the Columbia River (DOE 1). In order to assess why contamination is more prevalent in one section of the site, the 200 Areas in the Central Plateau (see Figure 1), I will look at two main geologic features that are present at the site: the vadose zone and clastic dikes (see Figures 2-4). I will then explain how each of these geologic factors plays a role in the area to show how the higher levels of contamination found within the Central Plateau is related to the dual presence of both the vadose zone and clastic dikes.
Coseismic Landslide Risk Assessment of the Carbon River Valley near Orting, WA
Landslides are a prevalent hazard in areas with steep slopes and heavy rains. This hazard risk increases with the presence of ground shaking caused by earthquakes. The goal of this project was to determine the coseismic landslide risk along a section of the Carbon River Valley near Orting, WA. The online software Scoops3D was used to find the Factor of Safety of the river valley walls and a Newmark Analysis was conducted using those results as well as peak ground acceleration values found using the USGS Unified Hazard Tool. The results of the Newmark Analysis fit the upper portion of the Weibull curve from Jibson et al. (2000), showing that there is a high probability for landslides in this area, even without the presence of ground shaking. The highest peak ground acceleration values would create the biggest hazard.
Assessing Potential Marine Iron Fertilization from Pacific Ocean Volcanic Systems
This project researched which volcanic arcs along the Pacific Ocean have the potential to induce marine primary productivity through iron (Fe) fertilization. To do so, published datasets of volcanic geochemical composition, ash deposition rates, and ocean Fe-limited zones were compiled and analyzed to assess the potential for iron fertilization. Arcs along the coast of Alaska and Asia were determined to have the highest overall Fe-fertilization potential. The Fe limited zones in the NW pacific ocean are predicted as the most likely places to experience Fe-Fertilization. This area, and the coast of south america, are the only places likely to experience the biological and economic benefits of volcanic iron fertilization.
Comparing Supraglacial and Proglacial Debris on Emmons Glacier, Mt. Rainier, Washington
Emmons Glacier, which is located on the Northeast flank of Mt. Rainier, Washington has an ablation zone and proglacial area that are covered in rock debris. In this study, hand sample field analysis, data synthesis, and analysis of aerial imagery were done to determine the origin of the debris in the supraglacial and proglacial areas. Rock samples analyzed along the surface of the glacier show a majority of angular clasts suggesting an origin of wasting, likely rockfalls. Rock samples from the proglacial zone show an overall rounded characteristic, meaning that the debris went through entrainment and tractional contact with the bed, likely through a subglacial fluvial system. Evidence of a large moulin and surface crevasses back up the theory of origin for the proglacial zone by being an avenue from which debris that has fallen onto the glacier can make its way into the entrainment process and on to the terminus of the glacier. A very large and complex proglacial stream system suggests a powerful subglacial fluvial environment capable of eroding the bed. High weathering of surface debris makes it likely that the surface cover is mainly from the 1963 Little Tahoma rockfall event, whereas, the lack of weathering on proglacial debris argues that newer material must be being added to the system from more recent rock falls or bed erosion.
Carbonate Rock with Encapsulated Petrified Wood in Channel of Skate Creek, WA
Black petrified wood was found in the Skate Creek channel near Packwood Wa within a rock unit that was visually identified as volcaniclastic sediment with carbonate matrix. The most updated USGS unit map does not clearly explain the origin of the petrified wood or the containing rock unit. The goals of the project was to understand: 1) what geological processes and/or event caused petrification of trees within the unit. 2) Why would the petrified wood be completely blackened. 3) How this rock unit compares to existing map units for the area. The methods used were stratigraphic and textural relations observed in the field as well as mineralogical and textural observations made with a petrologic microscope and scanning electron microscope (SEM). Unit was formed in a volcano-clastic mass wasting event that entrained large wood debris. The textural relationship and chemical similarity between the wood and the containing rock suggests that the wood was permineralized within the rock. Bytownite the original volcanic sediments were most likely intermediate – mafic composition. Chlorite and textural relationship with bytownite was found within the containing rock suggesting a metamorphic process up to greenschist facies. Veining texture within the permineralized wood, metamorphic minerals, and an increased bulk composition of CaCO3 suggest possible hydrothermal alteration. USGS map does not correctly identify the lithological unit at this location.
Analyzing Biogenic and Abiogenic Carbonate Dissolution in Ocean-Floor Sediments
Around the world today, we see a decrease in ocean pH levels, and this change in pH has potential devastating effects on marine ecosystems. This study examines the role of decreasing pH levels and associated dissolution rates of marine sediments, via analysis of the mineral calcite from biogenic and abiogenic sources; by means of a laboratory experiment setup. The study experimental setup mixed samples of ground biogenic (shells) and abiogenic (ooids) carbonate with aqueous solution at three pH levels (7,6, and 5). Rate and amount of calcite dissolution was measured for each experiment and byproducts of dissolution were analyzed via Ion Chromatography (IC). Data indicates increased dissolution as pH level decreases, which is concurrent with previous research, and IC analysis shows varying concentrations of anions in all samples. While some potentially harmful anions were detected, the concentrations are either in line with normal seawater or the results were inconclusive. More data via further decreasing pH levels will confirm or deny experimental findings.
Comparison of Intrabasinal and Extrabasinal Turbidites in Glacial Lake Systems
Turbidites are distinctive fining upward sedimentary sequences caused by density flows in water-based environments (Shanmugam, 1997). While most geologists learn of intrabasinal turbidites, which are caused by seismic and mass wasting events (Shanmugam, 1997), many do not know that similar features can be created from flooding events and are referred to as extrabasinal turbidites (Zavala, 2016). I analyzed two pervious study sites that were impacted by the Cordilleran Ice Sheet, Flathead Lake, MT (Hofmann et al. 2010), and Garden Gulch, MT (Smith 2016), to see if the determined turbidite conclusions matched the criteria established in Zavala et al. (2016). From Zavala et al. (2016), intrabasinal turbidites contain asymmetric ripples, coarse grains, and are geographically isolated, while extrabasinal turbidites have climbing ripples, fine grains, lamination, and are geographically un-isolated. Flathead lake was shown to have asymmetric ripples, fine grain lamination, and geographically un-isolated, while Garden Gulch had climbing ripples, a mixture of grain sizes, and fine grained lamination. Thus, I conclude that both Flathead lake and Garden gulch have extrabasinal turbidites, which agrees with Hofmann et al. (2010), but disagrees with Smith (2017).
Analysis of Surface Water Quality and Surface Geology Relationship in the Chambers-Clover Creek Watershed
This research regarding recent water quality analysis collection in collaboration with present surface geologic data was inspired by observations made while doing field work for the Environmental Methods 350 course at Pacific Lutheran. This project is derived from an interest in connecting those surface water qualities to surface geologic units, properties, and aquifers present within our Chambers-Clover Creek Watershed with the intention of connecting the interpretations of those data sets. Water quality parameters collected by environmental students were assessed and the water quality indices (WQI) at each site during each spring were calculated (Mitchell & Stapp, 1992). Surface geology, aquifer characteristics/locations and groundwater conductivity were assessed at Mayfair and Clover Creek Reserve sites (Savoca et al., 2010; Johnson et al., 2011). While the geologic and water quality properties are comparable at each study site, the presence of various aquifers potentially impacts those surface WQI based on infiltration rates, geologic characteristics, and groundwater flow patterns. My analysis of the current published data and connections to surface water quality did not provide significant improvements to the understanding of those connections in the CCCW, but does provide information that can be used in conjunction with further research on the topic.