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Timing and structural expression of the Nevadan orogeny, Sierra Nevada, California

1984; Geological Society of America; Volume: 95; Issue: 8 Linguagem: Inglês

10.1130/0016-7606(1984)95 2.0.co;2

1943-2674

Richard A. Schweickert, Nicholas L. Bogen, Gary H. Girty, Richard E. Hanson, Charles Merguerian,

earthquake and tectonic studies

Research Article| August 01, 1984 Timing and structural expression of the Nevadan orogeny, Sierra Nevada, California RICHARD A. SCHWEICKERT; RICHARD A. SCHWEICKERT 1Department of Geological Sciences and Mackay School of Mines, University of Nevada–Reno, Reno, Nevada 89557 Search for other works by this author on: GSW Google Scholar NICHOLAS L. BOGEN; NICHOLAS L. BOGEN 2Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109 Search for other works by this author on: GSW Google Scholar GARY H. GIRTY; GARY H. GIRTY 3Geology Department, University of Kansas, Lawrence, Kansas 66045 Search for other works by this author on: GSW Google Scholar RICHARD E. HANSON; RICHARD E. HANSON 4Department of Geology, School of Mines, University of Zambia, Lusaka, Zambia Search for other works by this author on: GSW Google Scholar CHARLES MERGUERIAN CHARLES MERGUERIAN 5Geology Department, Hofstra University, Hempstead, New York 11550 Search for other works by this author on: GSW Google Scholar Author and Article Information RICHARD A. SCHWEICKERT 1Department of Geological Sciences and Mackay School of Mines, University of Nevada–Reno, Reno, Nevada 89557 NICHOLAS L. BOGEN 2Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109 GARY H. GIRTY 3Geology Department, University of Kansas, Lawrence, Kansas 66045 RICHARD E. HANSON 4Department of Geology, School of Mines, University of Zambia, Lusaka, Zambia CHARLES MERGUERIAN 5Geology Department, Hofstra University, Hempstead, New York 11550 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1984) 95 (8): 967–979. https://doi.org/10.1130/0016-7606(1984)95 2.0.CO;2 Article history First Online: 01 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 RICHARD A. SCHWEICKERT, NICHOLAS L. BOGEN, GARY H. GIRTY, RICHARD E. HANSON, CHARLES MERGUERIAN; Timing and structural expression of the Nevadan orogeny, Sierra Nevada, California. GSA Bulletin 1984;; 95 (8): 967–979. doi: https://doi.org/10.1130/0016-7606(1984)95 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 SocietyGSA Bulletin Search Advanced Search Abstract The Nevadan orogeny was a very short-lived event in the Late Jurassic that involved the deformation of a great variety of rock types and Paleozoic and Mesozoic terranes throughout the extent of the Sierra Nevada. The Nevadan structures show great variation in style but relatively constant orientations. These relations can be explained by considering the prior histories of the various terranes.Slaty cleavages and tight folds are the characteristic main-phase structures in the western belt of Jurassic island-arc volcanic rocks and flysch-type sedimentary rocks. A strip of phyllites and greenschists along the eastern edge of the belt apparently represents similar Jurassic rocks that were deformed and metamorphosed at greater depths, probably during underthrusting of the western belt beneath the central belt. The central belt of Paleozoic metasedimentary and metavolcanic rocks shows the most extreme variation in style of main-phase structures, from weak, spaced to crenulation cleavages in the south, where polyphase deformed rocks formed a structural basement, to slaty and phyllitic cleavages and asymmetric to isoclinal folds in the north, where most of the Paleozoic basement rocks lack penetrative pre-Nevadan fabrics. Eastward-directed thrust faulting apparently was important only in the northern part of the range, where main-phase deformation was most intense. The eastern belt of Jurassic and Triassic magmatic arc-volcanic and sedimentary rocks defines the core of a major synclinorium, and the rocks contain penetrative slaty cleavages and asymmetric, tight to isoclinal folds.A late phase of Nevadan structures, consisting of northeast-trending cleavages and minor folds, also shows a marked variation in style, from relatively intensely developed in the north to very weakly developed in the south.The regional extent and geometry of the Nevadan structures indicate that the Nevadan orogeny involved underthrusting of island-arc rocks on the west and significant crustal shortening in the central and eastern belts. These features suggest that the Nevadan orogeny resulted from the collision of the island arc (western belt) with an andean-type arc (eastern belt) situated at the western edge of North America. 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.