Triassic blueschist from northern California and north-central Oregon

Research Article| November 01, 1977 Triassic blueschist from northern California and north-central Oregon Preston E. Hotz; Preston E. Hotz 1U.S. Geological Survey, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Marvin A. Lanphere; Marvin A. Lanphere 1U.S. Geological Survey, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Donald A. Swanson Donald A. Swanson 1U.S. Geological Survey, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Geology (1977) 5 (11): 659–663. https://doi.org/10.1130/0091-7613(1977)5<659:TBFNCA>2.0.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Preston E. Hotz, Marvin A. Lanphere, Donald A. Swanson; Triassic blueschist from northern California and north-central Oregon. Geology 1977;; 5 (11): 659–663. doi: https://doi.org/10.1130/0091-7613(1977)5<659:TBFNCA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Four samples of blueschist from the eastern Klamath Mountains near Yreka, northern California, and from north-central Oregon near Mitchell have radiometric ages of approximately 220 m.y. (Middle Triassic). In the Klamath Mountains, there are two types of blueschist occurrence: (1) tectonic blocks of mafic composition in a phyllitic quartzite and siliceous phyllite terrane, which has also undergone blueschist-facies meta-morphism and lies between a belt of serpentinite and an upper Paleozoic or lower Mesozoic greenstone-chert terrane, and (2) discontinuous layers and tectonic blocks in phyllitic rocks of the greenschist metamorphic facies, which occur beneath a thrust plate of lower Paleozoic sedimentary rocks. In north-central Oregon, blueschist blocks occur in strongly sheared upper Paleozoic metasedimentary and metavolcanic rocks overlain by Cretaceous sedimentary rocks. The blueschist blocks in the Klamath Mountains and north-central Oregon are inferred to have formed during subduction that accompanied widespread Middle Triassic tectonism in the western Cordillera. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.