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Date Permissions Signed

5-15-2018

Date of Award

Summer 1980

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Beck, Myrl E.

Second Advisor

Pevear, David R.

Third Advisor

Burmester, Russell F.

Abstract

Paleomagnetic directions from 34 widely distributed sampling sites in the Oligocene Ohanapecosh Formation in the Cascade Mountains of southern Washington are well grouped with a mean and confidence interval of: Dec. = 27°, Inc. = 64°, α95 = 4°. When compared to the expected direction, computed from the Oligocene reference pole for stable North America, a clockwise rotation of 31° ± 12° is apparently present. This result is not significantly different from other studies within the Cascades and Coast Range of southern Washington and suggests that the two Ranges have rotated as a single unit during late Eocene to mid-Oligocene time. Comparison with the results from rocks of similar age in Oregon suggests that at least two crustal blocks are involved in Pacific Northwest tectonics.

Type

Text

Keywords

Paleomagnetism, Oligocene, Pacific Northwest tectonics

DOI

https://doi.org/10.25710/yssa-ma33

Publisher

Western Washington University

OCLC Number

1054789937

Subject – LCSH

Paleomagnetism--Washington (State)--Cascade Range; Plate tectonics; Geology, Structural

Geographic Coverage

Cascade Range; Washington (State)

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

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