Physical Sciences and Mathematics Commons^™

Characterization Of The Shallow Subsurface Geohydrology Of The Ni-Les'tun Unit On The Bandon Marsh National Wildlife Refuge, Christopher Madison Beard

Dissertations and Theses

The Bandon Marsh is a large marsh restoration project located in southwest Oregon. The land has been previously used for dairy farms and much of the marsh was used for cattle grazing. The goal of the restoration is to recreate a natural habitat for shorebirds and fish. The purpose of this thesis is to gather and analyze data on the geology of the marsh and both ground and surface water quality to evaluate its ability to support biology.

The US Fish and Wildlife Service began restoration on the Bandon marsh in 2005. Research on the Ni-les'tun Unit began in that …

Grounding Zone Processes: Ice Mechanics And Margin Lakes, Kamb Ice Stream And Whillans Ice Stream, West Antarctica, Mason Joseph Fried

Dissertations and Theses

The lateral "corners" where Kamb and Whillans Ice Streams (KIS and WIS) discharge into the Ross Ice Shelf share common geometries and ice mechanical settings. At both corners of the now-stagnant KIS outlet, shear margins of apparently different ages confine regions with a relatively flat, smooth surface expression. These features are called the "Duckfoot" on the northern, right-lateral side and the "Goosefoot" on the other. It has been suggested, on evidence found in ice internal layers, that the flat ice terrains on KIS were afloat in the recent past, at a time when the ice stream grounding line was upstream …

Arsenic Mobility And Compositional Variability In High-Silica Ash Flow Tuffs, Courtney Beth Young Savoie

Dissertations and Theses

Volcanic rocks typically have only low to moderate arsenic concentrations, none-the-less, elevated levels of arsenic in ground waters have been associated with pyroclastic and volcaniclastic rocks and sediments in many parts of the world. The potential for arsenic leaching from these deposits is particularly problematic as they often comprise important water-bearing units in volcanic terrains. However, the role that chemical and mineralogical variations play in controlling the occurrence and mobility of arsenic from pyroclastic rocks is largely unexplored.

This study uses chemical and X-ray diffraction data to characterize and classify 49 samples of ash-flow tuffs, and 11 samples of tuffaceous …

Hydrogeologic Characterization Of Dutch Canyon, Scappoose, Oregon, Derrick Lee Wagner

Dissertations and Theses

Dutch Canyon is located directly west of the City of Scappoose in Columbia County Oregon. This area is proximate to Highway 30, a major access corridor to downtown Portland, and is experiencing a population increase, which is expected to continue and likely accelerate. As a result, there is growing pressure on water resources. Individual and community efforts to utilize groundwater resources have been hampered by generally poor groundwater yields and water quality concerns outside of the Columbia River corridor and a lack of published hydrogeologic information for the region.

The intent of this study is to identify the water-bearing units …

Investigations Into The Regional And Local Timescale Variations Of Subglacial Drainage Networks, Justin Hiester

Dissertations and Theses

Subglacial water plays an important role in the regulation of an ice sheet's mass balance. It may be the dominant control on the velocities of ice streams and outlet glaciers on scales of months to millennia. Recent satellite observations of ice surface elevation changes have given researchers new insights into how subglacial water is stored and transported. Localized uplift and settling of the ice surface implies that lakes exist beneath the ice sheet that are being filled and drained on relatively short time scales. %At the base of an ice sheet water can be transported through a variety of drainage …

Map-Based Probabilistic Infinite Slope Analysis Of The Stephens Creek Watershed, Portland, Oregon, Ryan Andrew Cole

Dissertations and Theses

The Stephens Creek Watershed in southwest Portland, Oregon was chosen by the city as a pilot project for urban stream restoration efforts, and the infiltration of stormwater was identified as a potential restoration strategy. The Stephens Creek Watershed has historically been known to be unstable during high precipitation events (Burns, 1996), and the need to address the response of slope stability to anthropogenically-driven changing groundwater conditions is the focus of this study. Airborne light detection and ranging (LiDAR) and geotechnical data from the City of Portland were employed to create a high resolution (0.84 m2) physics-based probabilistic slope stability model …

A Characterization Of Lake Abert Tufa Mounds Lake Abert, Oregon, Anthony Lynn Bartruff

Dissertations and Theses

A series of tufa mounds is found within the northern basin of Lake Abert, located within southeastern Oregon. The mounds have been divided into 3 main groups and 1 sub-group (A1, A2, B, and C) based upon spatial and textural considerations. Mound groups appear at two different elevations: the 1310 meter elevation (Groups A2, B, and C), and the 1318 meter elevation (Group A1). Published carbon age dating of the Lake Abert 1325 meter strandline and the 1310 meter strandline indicates that the mounds were formed during the Late Pleistocene/Early Holocene. Facies analysis and mineralogical analysis of the mounds indicates …

Arsenic In The Soils Of Northwest Oregon, Tracy Ryan Ricker

Dissertations and Theses

One hundred and eighty-six soil samples from Northwest Oregon were tested for arsenic content. The highest values measured were 13.9 ppm in the A horizon (site C4) and 20.4 ppm in the B horizon (Site P4). Arsenic was not detected in 28 A horizon samples and 23 B horizon samples. Data are grouped based on the age and rock type of underlying bedrock. Lithologic groups with six or more data points were compared statistically to ascertain if groups are distinct. Analysis of Variance (ANOVA) multiple comparison tests indicate that the arsenic content of the Marine Sediments and Sedimentary Rocks group …