Physical Sciences and Mathematics Commons^™

Structural And Biological Analysis Of Faults In Basalts In Sheepshead Mountains, Oregon As An Earth Analogue To Mars, Allison Bohanon

Theses and Dissertations

Microbial life on Mars is not visible from orbit or by rover cameras, but the fracture networks and scarp morphologies associated with fractures they could live in are measurable. We conducted a field analogue study of 92 normal fault scarps in the Sheepshead Mountains, Oregon to examine the correlation between scarp morphology and vegetation growth in the Steens Basalt. While vegetation is not expected on Mars, the fracture networks that sustain vegetation offer the same micro-environment that would support and protect endoliths. Structural variables were measured in the field and infrared spectra of fault scarps were measured using a handheld …

Slip Rates And Kinematics Of Active Crustal Faults In The Central Oregon Cascades, Katherine Alexander

WWU Graduate School Collection

New cosmogenic ³He chronologies and surficial geologic mapping constrain the age of glacial deposits and slip rates of predominantly normal faults in the White Branch and Dilman Meadows fault zones in central Oregon, USA, over the last ca. ~80 kyr. Our mapping of glacial landforms and deposits distinguishes three primary episodes of glacial deposition in the White Branch fault zone. Twenty-two new cosmogenic ³He surface exposure dates indicate that the youngest glacial unit represents a last glacial maximum deposit (ca. 19.4 +10.1/-6.2 kyr). Mapping of outwash terrace surfaces and deposits in the Dilman Meadows fault zone, constrained by …

Reconstructing Late Pleistocene And Holocene Paleoenvironments Using Playa-Lunette System Sediments Within The Harney Basin Of Southeastern Oregon, Usa, Joe Collins

Open Access Theses & Dissertations

Paleoenvironmental investigations of the Late Pleistocene and Early Holocene in the Harney Basin of eastern Oregon have been limited to date. This Dissertation investigates and links the stratigraphy of Rimrock Draw Rockshelter (35HA3855) (RDR) and two surrounding playas, Rimrock Lake and Hay Lake, located on the western margin of the Harney Basin, in order to identify paleoenvironmental shifts during the last ~20 kyr. An emphasis also is given to demonstrating the potential for playas in the Harney Basin to record changes in paleoclimate, as well as the application of multivariate statistics to interpret paleoenvironments from sedimentary grain size data. Stratigraphy …

The Geothermal System Near Paisley Oregon: A Tectonomagmatic Framework For Understanding The Geothermal Resource Potential Of Southeastern Oregon, Kyle Aaron Makovsky

Boise State University Theses and Dissertations

The tectonic and magmatic framework of southeast Oregon provides the conditions necessary for the existence of geothermal energy resources. However, few detailed studies of geothermal systems in this part of the Basin and Range have been conducted. Young bimodal magmatism and faulting associated with the High Lava Plains coupled with the encroachment of the Basin and Range tectonic province and potentially the Walker Lane have created the structural configuration, heat source, and secondary permeability necessary for geothermal systems in southeast Oregon. The relative contribution of these provinces to the overall tectonomagmatic framework is less well understood. In this study, the …

Characterization Of Mass Wasting Through The Spectral Analysis Of Lidar Imagery: Owyhee River, Southeastern Oregon, Christopher Earl Markley

All Master's Theses

Quantifying landslide character is an important aspect of understanding hillslope-channel interactions. Spectral analysis of high-resolution, LiDAR derived, DEMs was carried out following methods described by Booth et al. (2009) to determine the characteristic spectral signature inherent in different styles of landslides in the Owyhee River Canyon in southeastern Oregon. The main factor in landslide generation in this location is a lithologic contact in which a coherent basaltic caprock overlies relatively weak sediments where most of the landslide failure surfaces originated. Changes in spectral power distribution through time were quantified by comparing a sequence of adjacent rotational landslides of apparent different …

Lacustrine Sediment Record Of Multiple Quaternary Lava Dams On The Owyhee River, Southeastern Oregon, Caitlin Anne Orem

All Master's Theses

Multiple lava dams and correlating lakes impacted the Quaternary evolution of the Owyhee River. Sediment records from lava-dammed lakes were investigated to understand effects of the West Crater (WC) lava dam (~70 ka), the Saddle Butte 2 lava dam (~144 ka), and the Bogus Rim lava dam (~1.9 Ma). Evidence from the WC lava dam and related features indicates that dam duration consisted of five stages (1) dam and lake formation at ~70 ka; (2) dam overflow and lake sedimentation from ~70–46 ka; (3) removal of lava dam and lake termination from ~46 ka to at least 36 ka; (4) …

A Large Late Pleistocene Outburst Flood From Pluvial Lakes Alvord And Coyote Into The Owyhee River, Oregon, Deron Torrey Carter

All Master's Theses

A large late-Pleistocene flood traveled into the Owyhee River as a result of a rise and subsequent outburst from pluvial Lake Alvord in southeastern Oregon. Lake Alvord breached Big Sand Gap after reaching an elevation of 1292 m, releasing 11.3 km3 into the adjacent Coyote Basin before stabilizing at an elevation of about 1280 m. Overflow then spilled out of the Coyote Basin through two outlets at 1278 m and into the Crooked Creek drainage of the Owyhee River. The flood created a series of deeply incised canyons, scabland topography and deposited numerous boulder bars containing imbricated clasts up to …

Quaternary Amino Acid Geochronology Of The Lahontan Basin, Nevada, And The Chewaucan Basin, Oregon, Jeffrey Bigelow

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Amino acid geochronology based on fossil molluscs provides a useful approach to determining the Quaternary history of Great Basin lakes. The Lahontan basin, Nevada, and the Chewaucan basin, Oregon, in the northwest corner of the Great Basin, both contained lakes during the Quaternary. The aim of this study is to improve the Quaternary geochronology in these two basins by measuring time-dependent changes in amino acids preserved in fossil molluscan shells. The abundance of D-alloisoleucine relative to Lisoleucine (All) characterizes the extent of racemization, which increases with age and Ul forms the basis of relative and correlated ages. An age-calibration curve …

Pinuxylon Woolardii Sp. Nov., A New Petrified Taxon Of Pinaceae From The Miocene Basalts Of Eastern Oregon, William D. Tidwell, Lee R. Parker, Vaughn K. Folkman

Faculty Publications

Specimens of the new species Pinuxylon wollardii have been collected from Miocene strata near Kurkee, OR. These petrified specimens are unique in that, due to weathering, individual tracheids and ray cells can be separated for detailed SEM studies. This species is characterized by its high number of ray cells; numerous rays; large resin ducts which are commonly paired; primarily uniseriate pitting, two to five (usually three) small, oval or cirular pinoid pits per crossfield; and smooth walls on its transverse (ray) tracheids. The latter character relates this species to taxa in the subgenus Haploxylon of Pinus. Pinuxylon woolardii is most …

Geology And Hydrothermal Alteration, Glass Buttes, Southeast Oregon, Dulcy Annette Berri

Dissertations and Theses

The Glass Buttes volcanic complex consists of many domes and individual vents that erupted both rhyolitic and basaltic lavas during the late Miocene to early Pliocene. The east half of the complex, in the vicinity of Little Glass Butte, contains interfingering, finely flow-banded rhyolite and black obsidian flows. The youngest unit, an obsidian, has been dated at 4.9 m.y. East of Little Glass Butte lie two northwest-trending ridges, Antelope and Cascade Ridges, composed of two or more overlapping exogenous domes that formed along northwest-trending faults.

A Preliminary Investigation Of The Lithological Characteristics Of The Troutdale Formation In Portions Of The Camas, Sandy, Washougal, And Bridal Veil Quadrangles, David Lee Cole

Dissertations and Theses

The study area encompasses a region of about 80 square kilometers, centered about Corbett, Oregon. Sieve analyses suggest that the Troutdale Formation is composed of a conglomerate, a coarse-grained sandstone, and a siltstone lithofacies. Measured sections data show that 56 to 60 percent of the Troutdale Formation's exposures are composed of the conglomerate lithofacies. The coarsegrained sandstone lithofacies makes up 34 to 38 percent, while the siltstone lithofacies makes up only 4 to 8 percent. Pebble count data show that the representation of basalt varies from 69 to 100 percent, with an average of 85 percent, while quartzite varies from …

The Geology Of The Floras Creek Area, Curry County, Oregon, Jon Dudley Bounds

Dissertations and Theses

The Floras Creek area, east of the town of Langlois, near the southwest Oregon coast, includes Colebrooke Schist (a klippe of metamorphosed pelitic sediments of Jurassic age), Jurassic Otter Point Formation (a melange complex), and lower the middle Eocene Roseburg and Lookingglass Formations, part of a sandstone-shale sequence occurring more extensively in other areas. The Colebrooke Schist occurs in the south-central part of the area, bounded on the Otter Point and Roseburg. The Lookingglass is exposed as a small (1.5 sq. km) block in the north-north-west part of the area. Two major structural trends are found in the Floras Creek …

Geology Of The Southcentral Margin Of The Tillamook Highlands; Southwest Quarter Of The Enright Quadrangle, Tillamook County, Oregon, Kenneth Allan Cameron

Dissertations and Theses

The Tillamook Highlands is a largely unmapped volcanic pile located in the north end of the Coast Range of Oregon. The 36 square miles of T. 1 N., R. 8 W., on the southcentral margin of the Highlands, was chosen for detailed study.

The study area is composed of Eocene age sedimentary and volcanic units which were deposited in a filling basin. The lowest units were deposited in moderate to deep marine waters; the uppermost were deposited subaerially.

Petrology And Major Element Geochemistry Of Albite Granite Near Sparta, Oregon, Robert Brayton Almy Iii

WWU Graduate School Collection

Albite granite near Sparta, Oregon occurs in an igneous complex containing serpentinite, gabbro, diorite, tonalite and granite with overlying keratophyric and spilitic volcanic rocks. This igneous suite is overlain by Triassic limestones of reef origin. In all the igneous rocks primary hypidiomorphic and porphyritic textures predominate but a metamorphic overprint of the prehnite-pumpellyite facies is widespread. Whole rock chemical analyses show that albite granite has relatively high Si0₂ (69-81%) and Na₂0 (4-7%) and low K₂O (0.1-1%). Rare plagioclase potassium-feldspar granite contains up to 3.6% K₂O.

Although local isochemical alteration is demonstrable and local …