The geology and hydrothermal alteration of the Bear Creek Butte area, Crook County, central Oregon

Author

Richard Matthew Wilkening, Portland State University

Sponsor

Portland State University. Department of Geology

First Advisor

Michael L. Cummings

Date of Publication

1986

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Geology

Department

Geology

Language

English

Subjects

Geology -- Oregon -- Bear Creek Butte Region, Hydrothermal deposits -- Oregon -- Bear Creek Butte Region, Mineralogy -- Oregon -- Bear Creek Butte Region

DOI

10.15760/etd.5542

Physical Description

1 online resource (140 p.)

Abstract

The Eocene Clarno Formation, the Oligocene John Day Formation and basalts of the High Lava Plains are exposed in the Bear Creek Butte area in Central Oregon. In this area the Clarno Formation can be divided into a lower sequence composed of intermediate lava flows with intercalated mudflows and volcaniclastic sediments and an upper sequence of rhyolite and basalt flows and felsic ruffs. Separating the two units is a well developed saprolite. The change from intermediate to rhyolite-basalt volcanism reflects a change in the tectonic environment of the Cascade volcanic arc from compression to relaxation as subduction of the Farallon plate by the North American plate slowed, allowing extension of the continental plate margin to occur.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Comments

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Persistent Identifier

http://archives.pdx.edu/ds/psu/20642

Recommended Citation

Wilkening, Richard Matthew, "The geology and hydrothermal alteration of the Bear Creek Butte area, Crook County, central Oregon" (1986). Dissertations and Theses. Paper 3656.
https://doi.org/10.15760/etd.5542