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Post-Nevadan detachment faulting in the Klamath Mountains, California

Susan M. Cashman and Don R. Elder
Post-Nevadan detachment faulting in the Klamath Mountains, California
Geological Society of America Bulletin (December 2002) 114 (12): 1520-1534


A group of faults surrounding the Trinity terrane in the core of the Klamath Mountains province of northern California displays a commonality in physical features and in age that sets them apart from other faults in the Klamath Mountains. The faults dip shallowly outward from the central Trinity terrane and feature younger-on-older, detachment-fault geometry. Several exhibit shallowly south-southwest- or south-southeast-plunging slickenside striations. Distinctive muscovite-bearing dacite, muscovite-bearing rhyolite, and plagioclase porphyry dikes are common along these faults, as are epithermal mineralization and associated small, but economic gold and/or copper massive-sulfide deposits. Two of the faults crosscut the Triassic Siskiyou thrust. In addition, the Cecilville fault cuts the Late Jurassic Soap Creek Ridge fault, so extensional faulting postdates the widely developed Nevadan deformational event in the Klamath Mountains. A 126+ or -3 Ma KAr whole-rock age obtained on a muscovite-bearing rhyolite dike intruding the fault zone at Menzel Gulch, on the southern margin of the Trinity terrane, gives a minimum age of Early Cretaceous for this fault. Evidence for Tertiary extensional faulting on the La Grange fault, previously reported by Schweickert and Irwin, records a later episode of extension on the southern margin of the Trinity terrane.

ISSN: 0016-7606
EISSN: 1943-2674
Serial Title: Geological Society of America Bulletin
Serial Volume: 114
Serial Issue: 12
Title: Post-Nevadan detachment faulting in the Klamath Mountains, California
Affiliation: Humboldt State University, Department of Geology, Arcata, CA, United States
Pages: 1520-1534
Published: 200212
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 69
Accession Number: 2002-079363
Categories: Economic geology, geology of ore depositsStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables, geol. sketch maps
N41°00'00" - N43°00'00", W124°30'00" - W123°00'00"
N40°49'60" - N41°30'00", W122°55'00" - W122°15'00"
Secondary Affiliation: Klamath National Forest, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200224
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