Earth Sciences Commons^™

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.

Stratigraphy And Sedimentation Of The Spencer Formation In Yamhill And Washington Counties, Oregon, Fathi Ayoub Al-Azzaby

Dissertations and Theses

The Spencer Formation in Yamhill and Washington Counties, Oregon, is exposed in a narrow belt 27 km long, from 1/4 to 3 km wide and with a maximum thickness of about 400 m. The formation is composed entirely of sandstone with interbedded thin layers of mudstone in the uppermost member. The sedimentary structure and paleoecology indicate a shallow marine depositional environment. The upper member of the Spencer Formation contains more quartz, plagioclase, and hornblende than does the lower member, but K-feldspar is less than that of the lower member. Shallower water conditions for the deposition of the upper member are …

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.

"Energy Resources", Harrison Scott Brown

Special Collections: Oregon Public Speakers

With: Salter, C. L. The urban enigma.

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 …

Geology Of North Craters Of The Moon National Monument, Idaho, William C. Sidle

Dissertations and Theses

The purpose of the investigation was to map the geology of the north end of Craters of the Moon National Monument and surrounding area. A stratigraphic sequence of Late Paleozoic sedimentary and Tertiary volcanic rocks was compiles and the structures of these rocks and contact relationships with intrusions were delineated. Grade and facies of contact metamorphism were defined. The Snake River Plain basalts were also mapped. The sources of these flows were determined where possible. Preexisting structures and relationships of vents to earlier faulting were explored in ascertaining extensions of the Great Rift Zone into the Pioneer Mountains. Petrographic descriptions …

Stratigraphy And Sedimentary Petrology Of The Northwest Quarter Of The Dutchman Butte Quadrangle, Southwest Oregon, Thomas Edward Koler

Dissertations and Theses

The study area lies in southwest Douglas County 5 kilometers south from Camas Valley and is accessible by state highway 42. The purpose of the study was to map the geology at a 1:31,250 scale, determine the stratigraphy, study the petrology of the formations, and determine the provenance within a tectonic setting.

The Structure And Stratigraphy Of The Columbia River Basalt In The Hood River Valley, Oregon, Susan Timm

Dissertations and Theses

The Hood River Valley, located 100 kilometers east of Portland, Oregon, is in the transition zone between two geologic provinces--the High Cascades and the Columbia Plateau. The entire valley is probably underlain by Columbia River Basalt, but it crops out only on steep hillsides and in stream valleys. The base of the basalt is not exposed in the thesis area. The basalt is overlain by Pliocene and Quaternary basalt and andesite, volcanic sediments and glacial debris.

The stratigraphy of the Columbia River Basalt is useful in determining the path of the basalt flows into western Oregon, in mapping the structure …

Structural Geology Of The Southeast Quarter Of The Dutchman Butte Quadrangle, Oregon, Gerald Lee Black

Dissertations and Theses

Field work in the southeast quarter of the Dutchman ·Butte Quadrangle, which lies within the Klamath Mountains geomorphic province of southwestern Oregon, was completed during the summers of 1973 and 1974. The objectives of the study were fourfold: (1) to produce a geologic map of the southeast quarter of the Dutchman Butte Quadrangle, (2) to determine the nature of the contact between the Dothan and Rogue formations, (3) to construct a stratigraphic column of the Dothan Formation in the area, and (4) to attempt to determine the nature of the deformation occurring in the area.

The Stratigraphy And Structure Of The Columbia River Basalt In The Clackamas River Drainage, James Lee Anderson

Dissertations and Theses

The Clackamas River drainage within the western Cascade Range is approximately aligned with a northwest trending lineation defined by the Portland Hills and the Brothers Fault zone. This area is occupied by an extensive Columbia River Basalt sequence that is deeply incised by the Clackamas River and its tributaries. Two major basalt units of the Yakima Basalt Subgroup, including the Grande Ronde Basalt and the Frenchman Springs Member of the Wanapurn Basalt, are distinguishable in a 515 meter to 550 meter accumulation. Of particular interest is the presence of five trending right-lateral strike-slip faults is consistent with a stress model …

A Study Of Estuarine Sedimentation In South Slough, Coos Bay, Oregon, Charles Allen Baker

Dissertations and Theses

Sediments in the South Slough Estuarine Sanctuary, Coos Bay, Oregon, were sampled and studied in order to determine the sources, dispersal systems and depositional facies of sedimentation. The purpose of the study was to establish baseline measurements and observations on the existing sediment conditions within the relatively undisturbed South Slough Estuarine Sanctuary

Petrology Of The Bull-Of-The-Woods Intrusive Complex, James Streshley Jackson

Dissertations and Theses

An area of unmapped intrusions lies within the Bull-of-the-Woods Roadless Area of Mount Hood National Forest. A variety of andesites, dacites,and diorites intruding units of tuff and andesite lava flows crop out over.an area of 52 sq km. These intrusions do not appear on the Geologic Map of Oregon West of the 121st Meridian (Hells and Peck, 1961). The purpose of this investigation is to map and describe these intrusions, with attention to the following questions:

What is the petrographic and geochemical nature of these intrusions?

What is the order of emplacement of these intrusions?

What is the probable mechanism …

Stratigraphy And Petrography Of The Selah Member Of The Ellensburg Formation In South-Central Washington And North-Central Oregon, Mavis Hensley Kent

Dissertations and Theses

The Ellensburg Formation of south-central Washington and north-central Oregon has been described by many workers from the time of the original description by Russell (1893) to recent work by Schmincke (1964). However, detailed information concerning the stratigraphy and petrography of the Ellensburg Formation in south-central Washington and north-central Oregon is not available. This study is among the first detailed studies made for a member of the Ellensburg Formation; it provides a specific comparison with the type Ellensburg of central Washington.

Biostratigraphy Of The Type Weberg Member, Snowshoe Formation, Grant County, Oregon, David G. Taylor

Dissertations and Theses

Thirty three species of ammonites are recorded from the composite type section of the Weberg Member of the Snowshoe Formation in the Suplee area, Grant County, Oregon. Holcophylloceras burkei, Euhoploceras westi, E. tubereulosum and Strigoceras taylori are described as new, while four new species belonging to the genera Sonninia [?], Bradfordia, Pseudotoites and Witchellia are not formally named. Three ammonite zonules characterize the ammonite sequence of the type Weberg composite section. The sequence correlates with parts of the standard lower and middle Bajocian (Jurassic) of northwestern Europe. In addition, four associations (paleo-communities) of benthic mega invertebrates, the Gervillia, Protocardia, Isocyprina …

Analysis Of A Gravity Traverse South Of Portland, Oregon, Terry Dean Jones

Dissertations and Theses

The state gravity maps of Oregon and Washington show a gravity high centered south of Portland, Oregon and a gravity low in the Tualatin Valley to the west disrupting the regional gravity gradient which is controlled by crustal thickening. Detailed gravity surveys done in the Portland area are consistent with the state gravity maps but show considerably more detail. Quantitative interpretation of this data has provided new information on the subsurface structure in this area; recent work has yielded corroborative evidence for a fault zone bounding the east side of the Portland Hills, and has indicated the presence of faults …

The Petrology And Stratigraphy Of The Portland Hills Silt, Rodney Thomas Lentz

Dissertations and Theses

Topics in geology, which inevitably excite professional discussion and even tempered debate, often present challenging targets for the exploratory jabs of Master's degree candidates. The Portland Hills Silt and the controversy concerning its genesis provides just such an object.

Although the physical descriptions of the silt are generally in agreement, they remain somewhat generalized and, at present, no single definition is generally accepted. Moreover, incongruities concerning structural and textural details--notably, the presence of minor stratification and/or scattered pebbles in the silt--have resulted in considerable disagreement regarding its mode of origin.

Middle And Upper Eocene Biostratigraphy (Foraminifera) Of The Cascade Head Area, Lincoln And Tillamook Counties, Oregon, Arden D. Callender Jr.

Dissertations and Theses

An almost complete sequence of middle and upper marine strata, informally designated in this study as the "Strata of Cascade Head", has yielded 334 species and varieties of fossil Foraminifera. The Foraminifera were collected from 38 localities in four stratigraphic sections measured along the Salmon River, Neskowin Creek, Cascade Head Road, and near the town of Three Rocks in the central Oregon Coast Range.

Chlorine Distribution In The Idaho Batholith, Laurence Stewart Istas

Dissertations and Theses

Chlorine is thought to play a major role in the mobilization and concentration of base metals in the formation of ore deposits. The regional distribution of chlorine in the Idaho Batholith was studied to see if this could be related to mineralization or metallic provinces. One hundred forty-eight whole-rock samples, mineral separates, and standards were analyzed for chlorine by x-ray fluorescence.

The expected concentration of chlorine in the biotite fraction was not found. The chlorine was not significantly water leachable from the whole rock samples following normal grinding. The Idaho Batholith as a source for mineralizing chlorine was not established. …

Biostratigraphy Of The Snowshoe Formation (Jurassic) In The Izee Area, Grant County, Oregon, Paul Lawrence Smith

Dissertations and Theses

Using the standard Jurassic zonal scheme, this work attempts to determine the ages of the four members of the Snowshoe Formation that crop out in the Izee area. As a corollary, regional correlations are possible. The stratigraphic relationship between the Snowshoe Formation, the subjacent Hyde Formation and the superjacent Trowbridge Formation is also investigated.

Over one thousand fossils were collected from five stratigraphic sections and eight localities. The sections were measured using tape and compass techniques and the relative stratigraphic ranges of the fossils calculated using a computer program written specifically for this project. The ammonite fauna, dominated by the …

Stratigraphy, Structure, And Petrology Of The Snoqualmie Pass Area, Washington, Lawrence A. Chitwood

Dissertations and Theses

The Snoqualmie pass area lies about 50 mi (80 km) east of Seattle, Washington, along the crest of the Cascade Range. Five stratified units, forming a composite section over 22,000 ft (6700 m) thick, are recognized in the area. They were deformed and later intruded by granodiorite and quartz monzonite porphyry of the Snoqualmie batholith (middle Miocene). The oldest unit, the Denny Formation (Permian), 7000 ft (2100 m) thick, consists of interstratified basalt, andesite and dacite volcanic rocks and limestone and chert beds. This formation is unconformably overlain by a thick conformable sequence of early Tertiary strata which are subdivided, …

The Geology Of The Castle Rock Area, Grant, Harney And Malheur Counties, Oregon, John David Wood

Dissertations and Theses

The geology of the Castle Rock area aids in the understanding of Cenozoic volcanic stratigraphy and structures in an area where these volcanic rocks thin near the margins of the pre-Tertiary basement rocks and structural trends are overlapping. The Castle Rock area is unique in several aspects and is important in understanding and interpreting the geology in adjacent regions which have all been studied, at least on a regional basis. Intrusive ash-flow bodies of the Dinner Creek Ash-Flow Tuff, well-exposed sections of complexly interstratified volcanic rocks and well-exposed faults, and of high amount of erosional relief are features which make …

Structural Geology Of The Northeast Quarter Of The Dutchman Butte Quadrangle, Southwest Oregon, Rauno K. Perttu

Dissertations and Theses

The northeast quarter of the Dutchman Butte quadrangle straddles the boundary of the Mesozoic Klamath Mountains province and the Tertiary Coast Range province. The boundary in this area is controlled by a major easttrending fault zone, herein named the Canyonville fault zone. Jurassic Rogue, Dothan, and Otter Point Formations have been offset right-laterally at least 40 kilometers. In latest Jurassic and early Cretaceous time, the fault zone formed the shoreline along which sediments of the Myrtle Group were deposited.

Movement on the Canyonville fault zone becale down-to-the-north in Eocene time forming the southern margin of the Eocene Coast Range basin. …

Geology Of The Breitenbush Hot Springs Area, Cascade Range, Oregon, Clifford Michael Clayton

Dissertations and Theses

The Breitenbush Hot Springs area lies on the boundary of folded middle to late Tertiary Western Cascade rocks and younger High Cascade rocks. Within the mapped area the Western Cascade rocks are represented by four formations. The Detroit Beds, a sequence of interstratified tuffaceous sandstone, mudflow breccia, and tuff, is overlain unconformably by the Breitenbush Tuff. The Breitenbush Tuff consists of three units of welded pumice-rich crystal-vitric ash-flow tuffs interbedded with tuffaceous sedimentary rocks. The Outerson Formation unconformably overlies the Breitenbush Tuff and consists primarily of basaltic lava and breccia.

The Outerson Formation includes three localized members: a basal, glassy, …

Water Quality Within East Portland Terraces, Fouad Mohamed Tawfik

Dissertations and Theses

Groundwater from thirty-three wells which are randomly distributed within 42 square miles of the residential, agricultural and industrial area of East Portland Terraces have been analyzed. The area is moderately wet with an annual precipitation of about 37 inches. Residual and transported sediments from different sources, dominantly volcanic, comprise the subsurface lithology. The sedimentary units that were deposited by means of rivers and lakes have filled an original structural and erosional valley in the area. This relatively unconsolidated valley filling is about 900 feet of predominantly lenticular, stratified and cross-bedded lenses of clay, silt, sand, gravel, cobbles and boulders.

The …

A Mineralogical And Geochemical Study Of The Ferruginous Bauxite Deposits In Columbia County, Oregon, And Wahkiakum County, Washington, Ronald Laverne Jackson

Dissertations and Theses

Wet chemical analysis and instrumental neutron activation analysis (INAA) were performed on a suite of samples from three residual ferruginous bauxite profiles in the study area for abundances of Al₂O₃,

SiO₂, Fe₂O₃, Ti O₂, Na, Sc, Hf, Cr, Co, La, Sm, Yb, Lu, and Th. In addition a mineralogical study accompanied this research, using petrographic, differential thermal, and x-ray diffraction techniques. In each profile, the relative mobility of these elements were calculated by empirical methods for comparison with the parent rock and mineral properties in the saprolite.

This …

The Recognition, Investigation, Interpretation, And Treatment Of Landslides In The Pacific Northwest, Harry Ludowise

Dissertations and Theses

Certain features unique to the Pacific Northwest influence landsliding in this region. Weakly consolidated sediments, dense vegetation and seasonally concentrated rainfall all contribute to the distinctive conditions that are encountered here.

This study gathers together information applying to the recognition and correction of Pacific Northwest landslides. Treatment practices common to this region are discussed.

A large slide located about 30 miles east of Portland, Oregon along the Clackamas River is used as an example. Exploration, instrumentation, analysis and corrective measures are illustrated.

A Preliminary Investigation Of The Land Use Limitations Of The Major Landforms Along A Portion Of The Lincoln County Coast, Oregon, Richard Kent Mathiot

Dissertations and Theses

This study of a portion of Oregon's Lincoln County coast describes the physical limitations to land use of the various landforms in the study area. Seven major landform types comprise the study area: beaches, active dunes, stabilized dunes, marsh land and tidal flats, marine terraces, basaltic headlands, and uplands. Descriptions and evaluations of their physical characteristics, distribution, geologic and and engineering characteristics, and potentially hazardous processes are contained in the maps, figures, and text.