Stratigraphy and sedimentation of the Spencer Formation in Yamhill and Washington Counties, Oregon

Author

Fathi Ayoub Al-Azzaby, Portland State University

Sponsor

Portland State University. Department of Earth Sciences

First Advisor

Robert O. Van Atta

Date of Publication

1980

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Geology

Department

Earth Science

Language

English

Subjects

Stratigraphy, Sedimentology, Oregon, Sedimentary Rocks

DOI

10.15760/etd.3193

Physical Description

1 online resource (117 p.)

Abstract

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 indicated by sedimentary structures and the abundance of pebbly lenses and coaly material. Eighteen species of megafossils collected from the formation indicate that the Spencer Formation is of the Tejon stage (late Eocene of the West Coast).

Rights

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Comments

If you are the rightful copyright holder of this dissertation or thesis and wish to have it removed from the Open Access Collection, please submit a request to pdxscholar@pdx.edu and include clear identification of the work, preferably with URL

Plates 1 & 2 are available for download in the Additional Files below.

Persistent Identifier

http://archives.pdx.edu/ds/psu/18441

Recommended Citation

Al-Azzaby, Fathi Ayoub, "Stratigraphy and sedimentation of the Spencer Formation in Yamhill and Washington Counties, Oregon" (1980). Dissertations and Theses. Paper 3202.
https://doi.org/10.15760/etd.3193