Physical Sciences and Mathematics Commons^™

Description And Taphonomy Of A Turtle Assemblage (Chelonia: Trionychidae) In The Sentinel Butte Formation (Paleocene), Billings County, North Dakota, Glenn B. Kays

Theses and Dissertations

Soft-shelled turtle fossils (Family: Trionychidae) are common in Late Mesozoic and Early Cenozoic freshwater terrestrial deposits throughout western North America. Taxonomy of the Trionychidae is confusing for two reasons: 1) there are differences of opinion as to which characters are important in defining the lower systematic groups; 2) trionychid fossil material is often incomplete and fragmentary and has been used as the basis for numerous taxonomic descriptions.

The Ash Coulee Quarry is a fossil turtle assemblage located within the lower portion of the Sentinel Butte Formation (Paleocene) in Billings County, North Dakota. This quarry has produced at least 40 individual …

Hydrogeology And Paleohydrology In The Williamson River Basin, Klamath County, Oregon, Jeffrey Scott Conaway

Dissertations and Theses

Stress on the water resources of the Williamson River basin has led to their regulation to protect important habitat. Quantification of this resource is required for accurate regulation. A portion of this study is a hydrogeologic reconnaissance that suggests directions for future work. Measured discharge and deuterium isotope data from points above and below the Williamson River canyon indicate that the river receives 99% of its discharge from ground water during periods of low flow. The principle aquifer of the southern Klamath Marsh is a fractured basalt, while continental sediments that are up to 200 m thick provide high artesian …

Seismic Characterization Of The Northern Puget Lowland, Washington, Lori K. (Lori Kelly) Roberts

WWU Graduate School Collection

Records show that thousands of earthquakes have occurred in the northern Puget Lowland since 1969. At least fifteen of these events have been greater than magnitude 4, and one (Deming mag. 5.2, 1990) was the second largest recorded shallow crustal event in Washington for the last hundred years. Despite the evidence that suggests that the potential for great earthquakes capable of severe damage in the northern Puget Lowland is very real, the seismicity in the area is poorly understood. This is in part due to the wide scattering and apparently random assortment of recorded events. This thesis attempts to create …

Structure And Metamorphism Of The Talc Creek Area, Harrison Lake B.C., Minda L. Troost

WWU Graduate School Collection

The Slollicum and Cogburn terranes, metamorphosed country rock within the southern Coast Plutonic Complex, are juxtaposed along a thrust fault together with large slabs of ultramafic rock. The structure and metamorphism along and near this fault are the focus of this study.

Three periods of deformation (D₁-D₃) affected the study area. D₁ structures consist of penetrative foliation and lineations that are attributed to thrust stacking of the Slollicum and Cogburn terranes. Foliation, which parallels the fault contact, dips to the northeast at moderate to steep angles. Lineations have mainly down-dip orientations. D₂ structures record …

Stability Of Paleosinks And Karstic Carbonates In The Southern Fire Clay Mining District Of Missouri, Robert Weiser Dillon

Doctoral Dissertations

"The Southern Fire Clay District of Missouri was intensely mined during the late-1800’s to mid-1900’s for its valuable resource of high refractory clays deposited within Pennsylvanian sinkholes “paleosinks”. Mining operations have produced modifications in the Ozark aquifer, which in effect has possibly increased the instability of this paleokarst terrain and the potential of further environmental impacts to the land. Evidence supporting this hypothesis are: (1) A southerly shift in the regional groundwater divide relative to the topographic divide. This possibly is caused by the distribution of leaking clay pits, which suggests that the bedrock permeability or hydraulic conductivity has been …

A Fluid Inclusion And Structural Analysis Of The West Chance Vein System, Sunshine Mine, Kellogg, Idaho, David S. (David Scott) Boyer

WWU Graduate School Collection

The Sunshine mine, near Kellogg ID, is a mesothermal Ag-Pb vein deposit in the Coeur d’Alene mining district. Proterozoic siliciclastic rocks of the Ravalli Group, Belt Supergroup, host the ore bodies. The recently discovered West Chance ore body has been under development for the past five years. This tabular ore body strikes west and dips steeply to the south, has 300m (~1000 ft) strike length and extends approximately 914m (~3000 ft) down dip. Ore is located where the WNW-striking Chance fault changes to a predominately west-striking structure. This study consists of a fluid inclusion and structural analysis of the West …

Olivine Petrofabric Analysis From The Leka Ophiolite Complex, Sarah J. Titus

Honors Papers

Peridotites, gabbros and basaltic volcanic rocks on the island of Leka, Norway in the western Scandinavian Caledonides compose a nearly complete ophiolite sequence. I examined samples from the harzburgite to dunite transition within the ultramafic tectonites of the Leka Ophiolite Complex. This rock sequence probably corresponds to the petrologic Moho, which is the true base of the oceanic crust and lies below the seismic Moho. I used universal stage techniques to determine the crystallographic preferred orientations (CPO) of olivine grains in both dunites from the base of the oceanic crust and residual harzburgites in the uppermost upper mantle. Olivine CPOs …

Bridger Formation Sandstones Used As An Indication Of Tectonics In The Green River Basin And Western Wyoming, Lisa S. Novins

Honors Papers

Sandstone from the Eocene Bridger Formation of southwestern Wyoming can be used as a tool to constrain the timing and order of controversial tectonic events in the region. The key tectonic element in this region is the Wind River Range. Sandstones in the Bridger were derived from two source areas to the north, one being the basement rocks from the Wind River Range and the other volcanic rocks from the Absaroka Volcanic field (AVF). The abundance of volcanic grains increases upsection in the Bridger indicating that more volcanic material was carried through the Wind River Range. This evidence supports the …

Fine-Scale Strata Formation In Biologically And Physically Dominated Estuarine Systems Within The Lower Chesapeake And York River Subestuary, Timothy M. Dellapenna

Dissertations, Theses, and Masters Projects

To investigate the relationship between biological and physical mixing in forming strata, the lower mainstem of Chesapeake Bay has been contrasted with the York River Subestuary. By using radioisotope profiles from sediment cores, comparisons are made in terms of depth and rate of sediment mixing, deposition and accretion. Within the lower Chesapeake Bay two sites were selected as biologically dominated, both are located within the bay stem plains and are characterized by muddy sand and an abundance of large, deep-dwelling organisms. X-radiographs indicate complete biological reworking of sediments. 210Pb profiles reveal low sediment accretion rates within the mainstem sites ( …

Nitrate Reduction At The Groundwater - Salt Marsh Interface, Craig -1967 Tobias

Dissertations, Theses, and Masters Projects

The influence of groundwater discharge on the hydrology and biogeochemical cycling of nitrogen in a fringing intertidal wetland was studied by characterizing groundwater discharge, determining N-cycling rates in cores, and examining nitrate reduction in situ using 15N enrichment and natural gradient tracer techniques. Groundwater discharge was estimated by three independent methods: Darcy's Law, a water/salt mass balance, and a subsurface tracer test. Seasonal patterns of discharge predicted by Darcy's Law and the mass balance were similar. Discharge maxima and minima occurred in April and September, respectively. The water/salt mass balance provided the more reasonable estimate of groundwater flux at high …

Physical Control Of Biological Processes In The Central Equatorial Pacific: A Data Assimilative Modeling Study, Marjorie Anne Macwhorter Friedrichs

OES Theses and Dissertations

A five-component data assimilative ecosystem model is developed in order to investigate the effects of physical processes encompassing a wide range of space and time scales, on the lower trophic levels of the highly dynamic central equatorial Pacific (140°W). Many of the biological processes included in the ecosystem model respond to environmental fluctuations with time scales between one and ten days, which are not typically resolved by basin to global scale circulation models. Therefore, the ecosystem model is forced using daily observations from the TAO mooring array. Model simulations successfully reproduce data collected both during and after the 1991–92 El …

Sediment Dispersal And Sequence Development Along A Tectonically Active Margin: Late Quaternary Evolution Of The Ganges-Brahmaputra River Delta, Steven Lee Goodbred Jr.

Dissertations, Theses, and Masters Projects

Situated in the Bengal Basin, the Ganges-Brahmaputra river delta comprises one of the largest fluviodeltaic systems in the world, comprising ∼ 100,000 km2 of floodplain and delta plain and a 40,000 km2 subaqueous delta on the shelf. Sediment load of the Ganges-Brahmaputra river is 109 t/yr, and seasonal flooding may inundate >70% of the delta during large events. Active tectonic processes have resulted in both uplift and subsidence in this structurally complex region. These general characteristics suggest that the Ganges-Brahmaputra delta represents a heretofore undescribed delta end-member, forming along a high-yield, high-energy, tectonically active margin. to investigate this view, stratigraphic, …

Stratigraphy And Sedimentology Of The Pipestone Canyon Formation, North Central Washington, James Jenner Peterson

WWU Graduate School Collection

Since Mesozoic time, the western margin of North America has grown through the addition of tectonic terranes, transported atop the subducting paleo-Pacific oceanic plate. The “Baja British Columbia” terrane model postulates accretion of the Insular superterrane at the latitude of southern Mexico and subsequent, margin-parallel translation north to juxtaposition with the western portion of the Intermontane superterrane. After amalgamation, the composite block continued north to its current location. The timing of the proposed translation has not bear well constrained. In the study area, the Okanogan Range batholith of the Intermontane superterrane’s Quesnellia terrane is juxtaposed with the sedimentary and volcanic …

Nitrate Attenuation In A Narrow Non-Forested Riparian Buffer Zone In An Agricultural Watershed In Southern Ontario, Mark David Harris

Theses and Dissertations (Comprehensive)

Riparian buffer zones are defined as strips of natural vegetation separating streams or lakes from surrounding upland landscapes. These zones may effectively reduce the nitrate-N load in shallow ground water draining intensively fertilized agricultural regions. Contemporary research has tended to focus on wide, forested riparian zones situated on poorly drained lowland sites. In addition, research has typically focused on the growing season, when the ecosystem is biologically active, with relatively day hydrological conditions. This field study monitored spatial and temporal patterns of nitrate-N in a comparatively narrow, non-forested buffer zone situated in an upland agricultural watershed in southern Ontario. Results …