The vast majority of theses in this collection are open access and freely available. There are a small number of theses that have access restricted to the WWU campus. For off-campus access to a thesis labeled "Campus Only Access," please log in here with your WWU universal ID, or talk to your librarian about requesting the restricted thesis through interlibrary loan.
Date Permissions Signed
Date of Award
Master of Science (MS)
Brown, Edwin H.
Pevear, David R.
Babcock, R. Scott (Randall Scott)
Metavolcanic and metasedimentary rocks of the Shuksan Metamorphic Suite near Gee Point have been contact metamorphosed by high-temperature emplacement of ultramafic rock. This intrusion occurred at great depth (>25 km) and caused contact temperatures of about 500°C, resulting in epidote-amphibolite facies metamorphism. Minerals of the contact metamorphism are overprinted by mineral assemblages of the regional Shuksan blueschist facies metamorphism. The K/Ar age of the epidote-amphibolites is Jurassic (145-160 m.y.), and thus the age of Shuksan metamorphism is probably younger than Middle Jurassic.
Ultramafic rocks found near Gee Point have been metamorphosed to serpentinites during Shuksan metamorphism and should be considered part of the Shuksan Metamorphic Suite.
Shuksan blueschist facies metamorphism and the Gee Point epidote-amphibolite facies metamorphism probably occurred within a subduction zone. A tectonic model is proposed in which high-temperature ultramafic rock fills fractures and faults in a subducted plate, causing local contact metamorphism.
Comparison of metamorphic relations at Gee Point with rocks of the Franciscan Complex suggests that Franciscan eclogites may also result from contact metamorphism caused by ultramafic intrusions.
Shuksan blueschist facies
Western Washington University
Subject – LCSH
Ultrabasic rocks; Geology--Washington (State)--Skagit County; Serpentinite--Washington (State)--Skagit County; Crystalline rocks
Skagit County (Wash.)
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.
Wilson, Daniel L., "The Origin of Serpentinites Associated with the Shuksan Metamorphic Suite Near Gee Point, Washington" (1978). WWU Graduate School Collection. 779.