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Date Permissions Signed
2-15-2018
Date of Award
Spring 1981
Document Type
Masters Thesis
Degree Name
Master of Science (MS)
Department
Geology
First Advisor
Brown, Edwin H.
Second Advisor
Babcock, R. Scott (Randall Scott)
Third Advisor
Suczek, Christopher A., 1942-2014
Abstract
Detailed mapping of the Goat Mountain dunite and the western and southern margins of the Twin Sisters dunite indicates that the structural setting of these bodies is dominated by high-angle northwest-trending fault zones. The Goat Mountain dunite overlies rocks of the Chilliwack Group and Yellow Aster Complex as a lowangle, west-dipping slab approximately 2500 feet thick. Cretaceous phyllite west of Goat Mountain overlies Chilliwack Group rocks along a similar low-angle west-dipping fault contact. These structures are both truncated by high-angle fault zones.
The timing of faulting is poorly constrained. High-angle faulting is at least post-Eocene through Holocene (?), and may have begun as early as Late Cretaceous. Thrust emplacement of the Cretaceous phyllite over rocks of the Chilliwack Group may or may not have been contemporaneous with dunite emplacement.
Type
Text
Keywords
Goat Mountain dunite, North Cascades geology
DOI
https://doi.org/10.25710/45d4-eq31
Publisher
Western Washington University
OCLC Number
1027788529
Subject – LCSH
Geology--Washington (State)--Twin Sisters Range; Geology, Structural
Geographic Coverage
Twin Sisters Range (Wash.)
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.
Recommended Citation
Frasse, Frederic I., "Geology and Structure of the Western and Southern Margins of Twin Sisters Mountain, North Cascades, Washington" (1981). WWU Graduate School Collection. 639.
https://cedar.wwu.edu/wwuet/639
Plate 1 - Geologic Map of the Twin Sisters Area, North Cascades, Washington
Frasse Thesis Map 2 reduced 7272144.pdf (107 kB)
Plate 2 - Geologic Map of the Twin Sisters Area, North Cascades, Washington