Significance of Klamath rocks between the Franciscan Complex and Coast Range ophiolite, northern California

Tectonics
By: , and 

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Abstract

Small fault‐bounded slabs of low‐grade (prehnite‐pumpellyite‐bearing) slate, metagraywacke, and greenstone occur between the Coast Range ophiolite and South Fork Mountain Schist for at least 60 km south of the Klamath Mountains, northern California. The metagraywacke slabs differ from typical Franciscan Complex metagraywacke to the west by the absence of blueschist‐facies minerals and the abundance of quartz and chert clasts, and they differ from sandstone and mudstone of the Great Valley sequence to the east by the presence of a penetrative cleavage and low‐grade metamorphism. The metasedimentary rock in the slabs is petrographically identical to the Jurassic Galice Formation, which occurs along the western and southern margins of the Klamath Mountains. Upward drag along a west dipping reverse fault best explains the present structural position of the slabs and is consistent with available geological and geophysical data. These data imply that the Coast Range ophiolite structurally overlies Sierran‐Klamath basement at least locally.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Significance of Klamath rocks between the Franciscan Complex and Coast Range ophiolite, northern California
Series title Tectonics
DOI 10.1029/TC005i007p01055
Volume 5
Year Published 1986
Language English
Publisher American Geophysical Union
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 17 p.
First page 1055
Last page 1071
Country United States
State Oregon, Washington