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Date Permissions Signed

2-22-2018

Date of Award

Summer 2008

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Babcock, R. Scott (Randall Scott)

Second Advisor

Housen, Bernard Arthur

Third Advisor

Caplan-Auerbach, Jacqueline

Fourth Advisor

Linneman, Scott

Abstract

The results of a combined magnetic fabric and sedimentological investigation of trench and ridge structures along the foreslope of the Fraser Delta, British Columbia, indicate that turbidity currents are the likely origin of slope morphology. Evidence includes multiple and repetitive sequences of graded beds where trench and ridge structures are most pronounced and abundant. Distal to this region are fewer graded bedding sequences and increased evidence of hemipelagic deposition. A magnetic fabric analysis of cored sediments supports these conclusions. Stereographic projections of AMS ellipsoids from graded beds extracted from the mid-slope display characteristic turbidite relationships, whereas distal cores display hemipelagic relationships. In addition, a relative paleointensity investigation shows that deposition rates in the region of turbidite deposition are nearly an order of magnitude greater than at distal cores dominated by hemipelagic deposition. The results of this investigation suggest a foreslope sedimentation pattern of quiescent deposition punctuated by turbidite events, and evokes turbidites as the prime former of anomalous morphology. When analyzed in conjunction with sedimentological and magnetic results, turbidite influence along the foreslope appears to extend to a depth of approximately 130 meter below sea level.

Type

Text

Keywords

Foreslope sediments, submarine landslides, Tsunamigenic threat

DOI

https://doi.org/10.25710/vfb2-4h19

Publisher

Western Washington University

OCLC Number

1041855279

Subject – LCSH

Sediments (Geology)--British Columbia--Fraser River Delta; Sedimentation and deposition--British Columbia--Fraser River Delta; Landslide hazard analysis--British Columbia--Fraser River Delta; Turbidity; Tsunamis; Petrofabric analysis

Geographic Coverage

Fraser River Delta (B.C.)

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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