Physical Sciences and Mathematics Commons^™

Geochemical, Isotopic, And U-Pb Geochronologic Investigations Of Intrusive Basement Rocks From The Wallowa And Olds Ferry Arc Terranes, Blue Mountains Province, Oregon-Idaho, Gene Alan Kurz

Boise State University Theses and Dissertations

Late Paleozoic to Mesozoic arc terranes comprising the Blue Mountains Province of northeastern Oregon and western Idaho are poorly understood in terms of the timing and duration of recorded magmatism and deformation. Intrusive basement rocks of the Wallowa and Olds Ferry arc terranes are investigated using a combination of highprecision U-Pb geochronology, radiogenic isotope and trace element geochemistry, and structural geology to help constrain their tectonomagmatic evolution and to provide a better understanding for the accretionary history of the Blue Mountains Province.

The Cougar Creek Complex is a compositionally diverse intrusive complex interpreted as the mid-crustal portion of the Wallowa …

Structural And Stratigraphic Age Constraints Of The Inskip Formation, East Range, Nevada: Implications For Mesozoic Tectonics Of Western North America, Joshua David Wilkins

Boise State University Theses and Dissertations

Structural, stratigraphic, and U-Pb geochronologic studies of the Inskip Formation of the north-central East Range place new constraints on the depositional age of the Inskip Formation and the timing of contractional deformation in the East Range, including Golconda thrusting. The Inskip Formation was initially considered Permian in age and to rest unconformably on the Valmy (or Leach) Formation (Ferguson et al., 1951). Later mapping by Whitbread (1978, 1994) divided the formation into the Upper and Lower Inskip Formation, both of which were inferred to be Mississippian in age. Laterreinterpretation of Whitebread’s (1994) work and new paleontological data revised the age …

Factors Influencing Soil Moisture At The Hillslope Scale In A Semi-Arid Mountainous Environment, Ivan John Geroy

Boise State University Theses and Dissertations

Soil moisture couples ground, surface, and atmospheric water interactions via the processes of evapotranspiration, infiltration, and runoff generation (Grayson et al., 1997). Consequently, understanding the factors that influence the spatial distribution of soil moisture is vitally important to the accurate conceptualization and modeling of watershed processes. Typically, topographic indexing methods for the prediction of soil moisture have been studied in temperate or humid areas where the soil profile is often saturated and redistribution of soil moisture is driven by topography (Famiglietti et al., 1998; Grayson et al., 1997; Western et al., 1999). By contrast, in semi-arid environments, long periods of …

Characterization Of Englacial Voids Using Radar Velocity Anisotropy, Joshua D. Nichols

Boise State University Theses and Dissertations

Glacial hydrology plays an important role in the motion and melt of glaciers. The transport of water through glacial ice is still poorly understood. Previous studies show that much of the water is stored and routed through planar voids within the glacier. From borehole observations and previous radar surveys, the voids appear to have a preferential orientation. Transverse waves, including radar waves, and shear seismic waves, travel at different velocities when polarized at different orientations relative to aligned inclusions. I conducted two georadar surveys on Bench glacier, in the Chugach Mountains, AK. Bench glacier has been the field site of …

Age And Isotopic Investigations Of The Olds Ferry Terrane And Its Relations To Other Terranes Of The Blue Mountains Province, Eastern Oregon And West-Central Idaho, Kyle P. Tumpane

Boise State University Theses and Dissertations

The Olds Ferry terrane of the Blue Mountains province is one of the numerous accreted terranes that comprise the western North American Cordillera. The Blue Mountains province is located in central and eastern Oregon, western Idaho, and extreme southeastern Washington, and is a crucial link in reconstructions of the North American Cordillera due to its position in an area with few visible terranes between the more extensively exposed terranes to the south in California and Nevada and to the north in Canada and Alaska.

New field evidence and U-Pb zircon geochronology for volcanics within the sedimentary onlap assemblages overlying the …

Geochemical And Geochronological Constraints On The Tectonothermal History Of The Central And Eastern Nepal Himalaya: Implications For Thermal-Mechanical Models, Stacey Lynn Corrie

Boise State University Theses and Dissertations

Syntheses of Himalayan tectonics imply an average shortening rate of ~2 cm/yr across the Himalaya over the last 20-25 Myr. However, despite decades of research, basic questions still remain about how strain was partitioned. Fluctuations in the timing and rate of thrusting could have significant implications for strain partitioning across the Himalaya, and for partitioning during collisional orogenesis as a whole.

Due to the observed chronology and thermobarometry of Greater Himalayan Sequence (GHS) rock units in the Annapurna region of central Nepal, we revise the original interpretation of the Bhanuwa Fault from a normal fault to a thrust, and identify …

Using Soil Moisture Trends Across Topographic Gradients To Examine Controls On Semi-Arid Ecosystem Dynamics, Toni Jo Smith

Boise State University Theses and Dissertations

This study investigated controls on soil water storage and its effect on vegetation cover in a semi-arid, mountainous environment characterized by warm-dry summers and wet-cold winters. Soil moisture and soil temperature were monitored over 286 days at eight sites spanning four elevations (approx. 1100, 1300, 1500, and 1800 m asl), and paired north and south exposures. These sites span an ecological gradient from grass and shrub land to conifer forest. Measurements of soil texture, soil depth, vegetation cover (normalized difference vegetation index, NDVI), and soil carbon content were made at the same sites. Variables that strongly influence the soil water …

Identifying Controls On Surface Carbon Dioxide Efflux In A Semi-Arid Ecosystem, Katrina Elsie Ladd

Boise State University Theses and Dissertations

This study focused on soil respiration, the least constrained process in the terrestrial carbon cycle, and a source of uncertainty for model predicted ecosystem response to climate change. Respiration processes that make up soil respiration respond to environmental influencing factors, temperature, and moisture. Respiration responses vary by site, time of year, and also year to year, confounding determination of individual influence of the factors, making soil respiration difficult to model. This research took advantage of the climate characteristics of a semi-arid system, in order to observe soil temperature and moisture influence on soil respiration. Field measurements of soil surface CO …