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Date Permissions Signed

5-31-2018

Date of Award

Spring 1981

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Beck, Myrl E.

Second Advisor

Burmester, Russell F.

Third Advisor

Babcock, R. Scott (Randall Scott)

Abstract

The mean direction of remanent magnetism for 44 sampling sites from Oligo-Miocene lava flows in northern California points about 12° east of the expected Oligo-Miocene geomagnetic field direction for the area. Our paleomagnetic data and other data indicate that the Cascade Range has rotated clockwise since the middle Tertiary. Similar, but larger, clockwise rotations have been documented in previous studies throughout the Coast Ranges. Two mechanisms are suggested to account for the differential rotation that has occurred within the Coast and Cascade Ranges. First, the Coast Ranges are rotated and then accreted to a curved continental margin during the Eocene, leaving the Washington Coast Range relatively unrotated at the end of the Eocene. Secondly, during post- Eocene rotation, the thick crystalline crust of the Klamath Mountains prohibited the southern end of the Cascade Range from rotating as rapidly as the northern end, producing an oroclinal bend in the range.

Type

Text

Keywords

Paleomagnetism, Oligo-Miocene lava flows, Cascade Range

Publisher

Western Washington University

OCLC Number

1055420954

Digital Format

application/pdf

Comments

As with the original hardcopy of this thesis, pages 46 and 125 are missing and presumed to have never been included.

Geographic Coverage

Western Cascade Range; California

Genre/Form

masters theses

Language

English

Rights

Copying of this thesis 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.

Included in

Geology Commons

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