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Portland State University

Earth Sciences

1981

Articles 1 - 11 of 11

Full-Text Articles in Physical Sciences and Mathematics

The Determination Of A Relative Chronology For A Surface Archeological Site Using The Obsidian Hydration Dating Method, Scott Preston Thomas Nov 1981

The Determination Of A Relative Chronology For A Surface Archeological Site Using The Obsidian Hydration Dating Method, Scott Preston Thomas

Dissertations and Theses

This methodological study is an attempt to develop relative chronologies for surface archaeological sites from the obsidian hydration analysis of waste flake samples. Two sites in southeastern Oregon were selected and their surface components sampled. The results of the obsidian hydration analysis indicate, that with the use of random sampling methods and general geochemical control, a fairly accurate representation of the history of an archaeological surface site can be obtained.

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Stratigraphy, Lithofacies And Depositional Environment Of The Cowlitz Formation, T. 4 And 5n., R. 5w. Northwest Oregon, Dale M. Timmons Jan 1981

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.

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The Structure, Geologic Evolution And Regional Significance Of The Bethel Creek-North Fork Area, Coos And Curry Counties, Oregon, Carl Fredrick Gullixson Jan 1981

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.

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A Geochemical Study Of The Rhododendron And Dalles Formations In The Area Of Mount Hood, Oregon, Marshall W. Gannett Jan 1981

A Geochemical Study Of The Rhododendron And Dalles Formations In The Area Of Mount Hood, Oregon, Marshall W. Gannett

Dissertations and Theses

The Miocene Rhododendron and Dalles Formations in the Mount Hood area are accumulations of chiefly pyroclastic andesitic material, largely confined to the Dalles-Mount Hood syncline. These very similar units are geographically separated by overlying andesites including the present Mount Hood cone, and past workers (Hodge 1938, Wise 1969) have suspected that they may share a common source. Prior to this study, few geochemical data were available for the Rhododendron and the Dalles Formations, compared to the well studied Columbia River basalts underlying them and the overlying Pliocene andesites. This geochemical study was designed to investigate certain aspects of the Rhododendron …

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A Stratigraphic And Geochemical Investigation Of Ferruginous Bauxite Deposits In The Salem Hills, Marion County, Oregon, Charles William Hoffman Jan 1981

A Stratigraphic And Geochemical Investigation Of Ferruginous Bauxite Deposits In The Salem Hills, Marion County, Oregon, Charles William Hoffman

Dissertations and Theses

Pacific Northwest ferruginous bauxite deposits have formed in four main areas of northwestern Oregon and southwestern Washington by laterization of flows of the Columbia River Basalt Group (CRBG). The deposits, averaging 36.3% Al2O3 , 31.8% Fe2O3 , and 5.9% Sio2, generally occur near the surface of hilltops in gently rolling areas. Two very different views have been advanced regarding the setting in which the deposits have formed. The first hypothesis calls for a blanket-type laterization by erosion of much of the original deposit upon uplift and dissection of the area.

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The Influence Of Halloysite Content On The Shear Strength Of Kaolinite, Reka Katalin Gabor Jan 1981

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.

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The Stratigraphy And Structure Of The Columbia River Basalt Group In The Bull Run Watershed, Multnomah And Clackamas Counties, Oregon, Beverly Frobenius Vogt Jan 1981

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 …

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Geology Of A Volcanic Complex On The South Flank Of Mount Jefferson, Oregon, Brian Lee Gannon Jan 1981

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.

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Stratigraphy, Lithofacies, And Environment Of Deposition Of The Scappoose Formation In Central Columbia County, Oregon, Kevin Blair Kelty Jan 1981

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.

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Preliminary Inventory Of Lifeline Systems And Evaluation Of Seismic Hazards In Reno And Sparks, Nevada, Barbara Priest Jan 1981

Preliminary Inventory Of Lifeline Systems And Evaluation Of Seismic Hazards In Reno And Sparks, Nevada, Barbara Priest

Dissertations and Theses

The Reno-Sparks community is in a seismically hazardous area. Recent research indicates that a Richter 7.0 or greater magnitude earthquake could affect the area. Many of the emergency and essential facilities are situated in dangerous geological locations and are housed in outdated structures which could be severely damaged in the event of a major earthquake. Detailed site evaluations need to be made with respect to location of new structures and of existing building safety. The 1979 Unified Building Code seismic provisions should be adopted without exception; Nevada Revised Statute 278 .160 needs to be revised to require a seismic safety …

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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 Jan 1981

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.

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