Geology Commons^™

Structure And Evolution Of The Horse Heaven Hills In South-Central Washington, Michael Curtis Hagood

Dissertations and Theses

The Horse Heaven Hills uplift in south-central Washington consists of distinct northwest and northeast trends which merge in the lower Yakima Valley. The northwest trend is adjacent to and parallels the Rattlesnake-Wallula alignment (RAW; a part of the Olympic-Wallowa lineament). The northwest trend and northeast trend consist of aligned or en echelon anticlines and monoclines whose axes are generally oriented in the direction of the trend. At the intersection, folds in the northeast trend plunge onto and are terminated by folds of the northwest trend.

Geology, Alteration And Mineralization Of A Silicic Volcanic Center, Glass Buttes, Oregon, Michael James Johnson

Dissertations and Theses

Glass Buttes, a Pliocene silicic volcanic complex within the High Lava Plains province of Oregon, was erupted approximately 5.0 to 5.8 million years ago. Geologic mapping revealed that the eastern portion of the complex is underlain by rhyolitic glass domes, flows and rare pyroclastic flows. Basalt flows are interlayered with and onlap the silicic glass. Younger basalt flows, erupted from local vents, overlie silicic glass and onlapping basalts.

The eastern end of Glass Buttes is hydrothermally altered at the surface; a weak geothermal anomaly coincides with the altered areas. Alteration, localized by northwest trending normal faults, occurs primarily as opalite …

The Effect Of Viscosity On Impact Cratering And Possible Application To The Icy Satellites Of Saturn And Jupiter, Jonathan H. Fink, Donald Gault, Ronald Greeley

Geology Faculty Publications and Presentations

Impact experiments in Newtonian fluids with a range of viscosities of 10^-3 to 60 Pa s demonstrate that transient prater volume and shape (depth-to-diameter: ratio) depend on target viscosity as well as on gravity. Volume is reduced, and depth-to-diameter ratio is increased for cratering events in which viscosity plays a dominant role. In addition to being affected by target kinematic viscosity, viscous scaling is most strongly influenced by projectile diameter, less strongly by projectile velocity, and least strongly by gravity. In a Planetary context, viscols effects can occur for craters formed by small or slow moving impacting bodies, low …

Tiltmeter Analysis Of Mount St. Helens, Skamania County, Washington, Edward Charles Brown

Dissertations and Theses

Mount St. Helens returned to an active eruptive state March 20, 1980. Since then explosive and dome building eruptions have caused major topographic changes to the mountain and surrounding drainages. Monitoring of the southern side of the mountain by six tiltmeters at distances between 6 km and 12 km was conducted during the period of July 1, 1980 to December 31, 1980. Records obtained from the tiltmeters were analyzed and compared to data from precision geodetic surveys.

Igneous Dikes At Long Valley, Ca: Emplacement Mechanisms And Associated Geologic Structures, David D. Pollard, Jonathan H. Fink, Paul T. Delaney

Geology Faculty Publications and Presentations

Two hypotheses for dike emplacement are: (1) magma flows into and dilates pre-existing fractures; or (2) magma flows into and dilates self-generated fractures. In the first case dikes should be parallel to an element of the rock fabric; in the second, they should be perpendicular to the least compressive stress. The two hypotheses suggest different dike intrusion and fissure eruption mechanisms and therefore different strategies for monitoring igneous events at Long Valley. We derive a method to distinguish the two mechanisms, a priori, from in-situ stress measurements and estimates of magma pressure. Estimates of relative dilation and slip across a …

Quaternary Volcanology Of The West Crater-Soda Peaks Area, Southern Washington Cascade Range, David R. Polivka

Dissertations and Theses

The West Crater-Soda Peaks area covering about 100 km is located 35 km southeast of Mount St. Helens in southern Washington State. It is one of several Quaternary monogenetic High Cascade volcanic centers overlying the Ohaaapecosh Formation of the Western Cascade Group and interstratified glacial till.These volcanic centers are the most westerly of the range.

Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters

Dissertations and Theses

Over 1150 m of middle to late Eocene nonmarine arkose, lithic arkose, mudstone, and siltstone, referred to here as the Chambers Creek beds, are int~r.stratified with, and overlain by over 1600 m of late Eocene-Oligocsne(?) andesitic volcaniclastic and subordinate volcanic rocks assigned to the Ohanapecosh Formation, in a dissected structural high in the southern Washington Cascade Range, about 18 km south-southeast of the town of Packwood.

Depositional Model Of The Antelope Coal Field, Wyoming, Christine M. Budai

Dissertations and Theses

The coal-bearing sediments of the Antelope coal field in the southcentral Powder River Basin, Wyoming were deposited in paludal and tributary subsystems of the fluvial system that existed in the basin during the early Tertiary. A depositional model for the Antelope coal field was constructed from data collected from approximately 500 drill holes that penetrated the upper 90 meters (300 feet) of the Fort Union Formation. The depositional environments were interpreted from lithologic descriptions and guidelines established in the literature.

The two main coal seams at the Antelope coal field are the Anderson and stratigraphically lower Canyon coal seams. They …

Holocene Geologic History Of The Clatsop Plains Foredune Ridge Complex, David Karl Rankin

Dissertations and Theses

This research formulated a recent geologic history of the Clatsop Plains dating from 3500 years BP to present. Research consisted of geomorphic mapping, near-surface stratigraphic evaluation, carbon dating and subsurface interpretation of available data.

Formation And Zonation Of Ferruginous Bauxite Deposits Of The Chapman Quadrangle, Oregon, Richard Charles Marty

Dissertations and Theses

Two major theories have been advanced to account for the scattered distribution of ferruginous bauxite deposits. Original workers proposed that ferruginous bauxite originally developed over all exposed Columbia River Basalt in western Oregon and was subsequently removed by erosion. Studies which followed have suggested that it may be locally favorable conditions, especially of drainage, which are responsible for deposit distribution. Field mapping in the Chapman Quadrangle shows a possible correlation between a series of sheared zones, which may have improved drainage, and the distribution of ferruginous bauxite deposits. Examination of the pisolitic zone ferruginous bauxite of the Chapman Quadrangle failed …

Stratigraphic Relationships Of The Tillamook Volcanics And The Cowlitz Formation In The Upper Nehalem River-Wolf Creek Area, Northwestern Oregon, Michael Keith Jackson

Dissertations and Theses

The upper Nehalem River-Wolf Creek area is located on the northeastern flank of the Tillamook Highlands in the northern Oregon Coast Range. Three rock stratigraphic units underlie the thesis area, and these units range from late Eocene to Oligocene in age.

A Study Of The Diagenesis Of The Overburden Between The Badger And School Coal Seams, Dave Johnston Coal Field, Converse County, Wyoming, Rebecca K. Jaffer

Dissertations and Theses

Low pH zones in portions of the overburden at the Dave Johnston Coal Field, Converse County, Wyoming are the subject of this study. The low pH zones are restricted to limonite stained sandstones which grade downdip into normal pH gray sandstones. Changes in color, clay mineralogy, cementation and feldspar surface textures are noted between the two sandstone units. These changes appear to be the result of post depositional alteration that was responsible for oxidation of pyrite and chlorite, dissoluion of calcite, and the etching of feldspar grains. The parameters for the diagenesis fit those of uranium roll front models proposed …

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 …

A Geophysical Study Of The North Scappoose Creek, Alder Creek, Clatskanie River Lineament, Along The Trend Of The Portland Hills Fault, Columbia County, Oregon, Nina Haas

Dissertations and Theses

The Portland Hills fault forms a strong northwest trending lineament along the east side of the Tualatin Mountains. An en echelon lineament follows North Scappoose Creek, Alder Creek, and the Clatskanie River along the same trend, through Columbia County, Oregon. The possibility that this lineament follows a fault or fault zone was investigated in this study. Geophysical methods were used, with seismic refraction, magnetic and gravity lines run perpendicular to the lineament. The seismic refraction models indicate the near surface basalt is broken in many places, with 15 - 30 meters (50 - 100 feet) vertical displacement, down to the …

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.

The Stratigraphic Relationships Of The Columbia River Basalt Group In The Lower Columbia River Gorge Of Oregon And Washington, Terry Leo Tolan

Dissertations and Theses

The purpose of this study was to produce a detailed geologic map of the CRBG in the western portion of the Columbia River Gorge (fig. 1). The objectives were (1) to identify and delineate the extent of the Priest Rapids Member and Pomona Member intracanyon flows, and (2) to define the relationship of post-CRBG units to the CRBG intracanyon flows.

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 Influence Of Halloysite Content On The Shear Strength Of Kaolinite, Reka Katalin Gabor

Dissertations and Theses

The objective of this thesis is to determine the relative shear strengths of halloysite, kaolinite, synthetic mixtures, and local soils, to investigate the influence of halloysite content on the shear strength of kaolinite, and to explore the possibility that the strength properties of soil clays might be controlled by the relative content of their component minerals.

Geology Of A Volcanic Complex On The South Flank Of Mount Jefferson, Oregon, Brian Lee Gannon

Dissertations and Theses

The volcanic stratigraphy and petrography is described for a 46 km² area on the southern flank of Mount Jefferson in the north-central part of the Oregon High Cascades. Here, volcanic processes have been active throughout Quaternary time, resulting in complex stratigraphic relationships. In addition, three formerly recognized glaciations and a two-phase period of neoglaciation have eroded the terrain, depositing tills in contact or interstratified with the volcanic units. Collectively, these processes and the resulting deposits are characteristic of High Cascades development.

The Structure, Geologic Evolution And Regional Significance Of The Bethel Creek-North Fork Area, Coos And Curry Counties, Oregon, Carl Fredrick Gullixson

Dissertations and Theses

The original purpose of this study was a detailed structural analysis of the Jurassic Otter Point Formation in order to determine if the Canyonville Fault Zone, which forms the northern boundary of the Klamath Mountains in the Riddle - Canyonville area (Benson and Perttu, 1980), extends westward to the coast and, if possible, to characterize the structure of the Otter Point Formation. Further, a detailed examination of the structural and stratigraphic relationships between the Otter Point Formation and the Eocene Roseburg and Lookingglass Formations was to be performed in an attempt to determine the tectonic history of the area.

Stratigraphy, Lithofacies And Depositional Environment Of The Cowlitz Formation, T. 4 And 5n., R. 5w. Northwest Oregon, Dale M. Timmons

Dissertations and Theses

The Cowlitz Formation in southern Columbia and Clatsop counties, northwest Oregon was studied in order to prepare a geologic map of parts of this formation and to determine the character of its lithofacies and the environments of deposition.

The Stratigraphy And Structure Of The Columbia River Basalt Group In The Bull Run Watershed, Multnomah And Clackamas Counties, Oregon, Beverly Frobenius Vogt

Dissertations and Theses

Approximately 150 meters (500 feet) of Grande Ronde Basalt and 140 meters (450 feet) of Wanapum Basalt of the Columbia River Basalt Group are exposed in the Bull Run Watershed. In Bull Run, the Grande Ronde Basalt is divided into three mappable units: "low Mg" R₂ (at least one flow), "low Mg" N₂ (approximately four flows), and "high Mg" N₂ (two to three flows}. The Wanapum Basalt is represented by two members: Frenchman Springs Member (six flows) and Priest Rapids Member (one flow). These units are identified by instrumental neutron activation analysis, paleomagnetism based on measurements with …

Stratigraphy, Lithofacies, And Environment Of Deposition Of The Scappoose Formation In Central Columbia County, Oregon, Kevin Blair Kelty

Dissertations and Theses

The study area is located in central Columbia County and encompasses approximately 373 square kilometers. The purpose of the study was to map lithofacies to a scale of 1:31250, study the petrography of the lithofacies, determine the stratigraphy, and develop a model for environment of deposition of the Scappoose Formation.

Rheological Properties Of Mudflows Associated With The May 1980 Eruptions Of Mount St. Helens Volcano, Washington, Jonathan H. Fink, Michael C. Malin, Richard E. D'Alli, Ronald Greeley

Geology Faculty Publications and Presentations

Rheological properties of three recent mudflows at Mount St. Helens were estimated using techniques developed for determining the properties of debris flows based on the geometry of their deposits. Calculated yield strengths of 1100, 1000, and 400 Pa, maximum flow velocities of 10 to 31 m/s, volumetric flow rates of 300 to 3400 m³/s, and plastic viscosities of 20 to 320 Pa-s all compare favorably with measured and estimated values cited in the literature. A method for determining likely sites of future mudflow initiation based on these data is outlined.

An Analysis Of Gravity Surveys In The Portland Basin, Oregon, Janice C. Perttu

Dissertations and Theses

The geologic setting of the Portland Basin is ideal for gravity surveys because of the large density contrasts between geologic units. The Portland Basin consists of a north-northwest-trending syncline in the Columbia River basalt overlain by Pliocene to Recent alluvium. This study was undertaken to define structures in the Portland Basin which are obscured by the alluvium.

An areal gravity survey of the Portland Basin covering approximately 450 square kilometers was conducted for this study.

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.

The Structure And Stratigraphy Of The Columbia River Basalt In The Chehalem Mountains, Oregon, Abdul-Rahman Mohammed Al-Eisa

Dissertations and Theses

The Chehalem Mountains area, encompassing 70 square kilometers, is at the western extent of the Columbia River Basalt Group as mapped in western Oregon. The flows in the study area were identified as belonging to subdivisions of the Columbia River Basalt Group on the basis of physical characteristics and trace element geochemistry. The basalt flows are poorly exposed in the area and weathering is deep and extensive where the flows have been exposed. Where erosion has exposed the underlying marine sedimentary rocks, the basalt has failed in landslides.

Geology Of The Columbia River Basalt In Silver Falls State Park, Oregon, Elizabeth Storm Norman

University Honors Theses

Silver Falls State Park is near the southern extent of the Columbia River Basalt Group as mapped in western Oregon. The flows in the park were identified as belonging to subdivisions of the Columbia River Basalt Group on the basis of physical characteristics and trace element geochemistry. The sequence of flows present is as follows: 3-4 flows of the Low-Mg chemical type of the Grande Ronde Basalt, 2 flows of the High-Mg chemical type of the Grande Ronde Basalt, 3 flows of the Frenchman Springs Member of the Wanapum Basalt, and one flow of anomolous geochemistry. The flows dip west …

A Geophysical Definition Of A Klamath Falls Graben Fault, Cynthis Ann Veen

Dissertations and Theses

Four geophysical methods, along with well logs and outcrop data, were used in determining the location of a fault situated on the campus of Oregon Institute of Technology, just north of Klamath Falls, Oregon. The fault displaces rocks of the Yonna Formation, of Pliocene age. Wells located northeast of the fault (on the upthrown side) produce cold water, and wells located southwest of the fault (on the downthrown side) produce hot water. The purpose of this investigation was to define the characteristics of the fault exposed behind a large water tank southeast of the OIT campus.

The Geology And Geochemistry Of The North Fork Stock, Northeastern Oregon, David Joseph Matty

Dissertations and Theses

The North Fork stock is a composite intrusive body of Late Jurassic-Early Cretaceous age which outcrops in the Blue Mountains of northeastern Oregon. The upper 600 m of the intrusion are exposed over an area of approximately 36 km² along the canyon walls of the North Fork of the John Day River in Grant and Umatilla counties. The stock intrudes metasediments, metavolcanics, and metagabbros associated with the Permian-Triassic Elkhorn Ridge Argillite. Contact metamorphism of the Elkhorn Ridge Argillite is developed to the hornblende-hornfels facies throughout most of the exposed area of this unit in the study area. The contact …