Geology Commons^™

A Tectonic Study Of A Part Of The Northern Eagle Cap Wilderness Area, Northeastern Oregon, Kenneth Gordon Neal

Dissertations and Theses

Upper Triassic metavolcanic and metasedimentary strata in the study area are intruded by the Hurricane Divide and Craig Mountain Plutons of the Late Jurassic-Cretaceous Wallowa Batholith. The Clover Creek Greenstone is overlain by the Martin Bridge Limestone, which is in tum overlain by the Hurwal Argillite; although the sequence is in normal stratigraphic order, contacts are generally tectonic. Concurrent with Early-Middle Jurassic regional deformation, during intermediate to mafic dikes, emplacement of the plutons of the Wallowa Batholith began. The plutons intruded vertically through the greenstone and limestone and then horizontally above the greenstone. This resulted in intense penetrative plastic deformation …

The Characteristics And Genesis Of Stone Stripes In North Central Oregon, John Baine Pyrch

Dissertations and Theses

Stone stripes are linear accumulations of rock debris separated by finer material and oriented down the steepest available slope. In north central Oregon, the stone stripes are composed of basalt fragments and occur where the soil mantle averages less than 1 m in depth. They are best developed in areas of higher elevation, usually from about 900 to 1100 m, and are most prominent on convex to straight slopes of 15 to 30 degrees. The stripes vary from a few meters to over 150 in length, and their widths range from 0.3 to over 3 m. The depth of the …

Granulometric Analysis Of Recent Sediments Of Tillamook Bay, Oregon, Gennaro William Avolio

Dissertations and Theses

The author has sampled the recent bottom sediments in Tillamook Bay, Oregon. Sediment distribution is assessed in relation to sediment source areas and related to sedimentary environments. Particular attention was directed to the precision with which granulometric data can be stated. It was found that variance is quite high for granulometric parameters of the bay sediments.

Sediment distribution using different measures are displayed on charts of the bay. Size distributions of sediments at any given location are examined for geologic significance. Plotting of size distribution on graph paper using probability ordinate is shown to increase the ease of geologic interpretation. …

The Geology Of The Southeast Quarter Of The Bone Mountain Quadrangle, Oregon, Richard Cortland Kent

Dissertations and Theses

This thesis is a study of the geology of the southeast quarter of the Bone Mountain Quadrangle. The bedrock geology mapped includes about 56 square miles.The Klamath Mountain and Coast Range Provinces of southwestern Oregon are represented in the area. Rocks in the area include the Rogue, Dothan Riddle, Days Creek, upper member of the Umpqua and Tyee Formations. The ages of these rocks range from Late Jurassic to middle Eocene. Late Jurassic ultramafic and mafic intrusive rocks associated with the Rogue Formation occur in the Klamath Province. The metavolcanics of the Rogue Format ion and an associated linear belt …

Geophysical And Geological Analysis Of A Fault-Like Linearity In The Lower Clackamas River Area, Clackamas County, Oregon, Ronald Jay Schmela

Dissertations and Theses

A fault-like linearity along the lower Clackamas River is evaluated by analysis of physiographic and structural alignments, geological relationships, and by gravity and magnetic data. The study has resulted in the verification of a structural feature extending along the Clackamas River and the eastern front of the Portland Hills. Physiographic alignments were examined in twelve 15 minute and two 7-1/2 minute quadrangle maps. A significant northeasterly morphologic trend, N. 20⁰ W. and N. 40° W., and other secondary trends, namely, the N-S, E-W, and N. 50-60° E., has developed in the Portland area. The consistent northwest trend is observed throughout …