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Date Permissions Signed

6-7-2018

Date of Award

Summer 2004

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Housen, Bernard Arthur

Second Advisor

Burmester, Russell F.

Third Advisor

Crider, Juliet G.

Abstract

Paleomagnetic investigation of Upper Cretaceous sedimentary strata of the Point Arena terrane has shown the rocks to be remagnetized. The study was initially intended to reconstruct the Cretaceous paleogeography of the Point Arena terrane and resolve conflicting translation estimates, but became one of remagnetization. Samples studied are from the Upper Cretaceous Stewart’s Point member and the Late Cretaceous Anchor Bay Member of the Gualala formation. Specimens surviving the remagnetization have a mean second-removed direction that indicates approximately 20 degrees vertical rotation from the expected direction of the Cretaceous magnetic field at the locality of the Point Arena terrane. The loss of original magnetization is most likely the result of a ChRM (chemical remanent magnetization) caused by orogenic fluid circulation. Reheating as the remagnetization mechanism can be ruled out by total lack of metamorphism. The paleomagnetic results of this study confirm a complex tectonic history for the Point Arena terrane. Once the nature and timing of the remagnetization events are better understood a more complete tectonic history can be determined.

Type

Text

Keywords

Paleomagnetism, Remagnetization, Paleogeography

DOI

https://doi.org/10.25710/sckg-gr59

Publisher

Western Washington University

OCLC Number

1052898047

Subject – LCSH

Paleomagnetism--California--Arena, Point; Paleogreography--Cretaceous; Geology--California--Arena Point

Geographic Coverage

Arena, Point (Calif.)

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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