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Deformation during terrane accretion in the Saint Elias orogen, Alaska

2004; Geological Society of America; Volume: 116; Issue: 7 Linguagem: Inglês

10.1130/b25182.1

1943-2674

Ronald L. Bruhn, Terry L. Pavlis, George Plafker, Laura Serpa,

Geological and Geochemical Analysis

Research Article| July 01, 2004 Deformation during terrane accretion in the Saint Elias orogen, Alaska Ronald L. Bruhn; Ronald L. Bruhn 1Department of Geology and Geophysics, University of Utah, 135 South, 1460 East, Room 719, Salt Lake City, Utah 84112-0111, USA Search for other works by this author on: GSW Google Scholar Terry L. Pavlis; Terry L. Pavlis 2Department of Geology and Geophysics, University of New Orleans, 2000 Lakeshore Drive, New Orleans, Louisiana 70148, USA Search for other works by this author on: GSW Google Scholar George Plafker; George Plafker 3U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA Search for other works by this author on: GSW Google Scholar Laura Serpa Laura Serpa 4Department of Geology and Geophysics, University of New Orleans, New Orleans, Louisiana, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Ronald L. Bruhn 1Department of Geology and Geophysics, University of Utah, 135 South, 1460 East, Room 719, Salt Lake City, Utah 84112-0111, USA Terry L. Pavlis 2Department of Geology and Geophysics, University of New Orleans, 2000 Lakeshore Drive, New Orleans, Louisiana 70148, USA George Plafker 3U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA Laura Serpa 4Department of Geology and Geophysics, University of New Orleans, New Orleans, Louisiana, USA Publisher: Geological Society of America Received: 15 May 2002 Revision Received: 20 Feb 2003 Accepted: 09 Jun 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2004) 116 (7-8): 771–787. https://doi.org/10.1130/B25182.1 Article history Received: 15 May 2002 Revision Received: 20 Feb 2003 Accepted: 09 Jun 2003 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Ronald L. Bruhn, Terry L. Pavlis, George Plafker, Laura Serpa; Deformation during terrane accretion in the Saint Elias orogen, Alaska. GSA Bulletin 2004;; 116 (7-8): 771–787. doi: https://doi.org/10.1130/B25182.1 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 Saint Elias orogen of southern Alaska and adjacent Canada is a complex belt of mountains formed by collision and accretion of the Yakutat terrane into the transition zone from transform faulting to subduction in the northeast Pacific. The orogen is an active analog for tectonic processes that formed much of the North American Cordillera, and is also an important site to study (1) the relationships between climate and tectonics, and (2) structures that generate large- to great-magnitude earthquakes. The Yakutat terrane is a fragment of the North American plate margin that is partly subducted beneath and partly accreted to the continental margin of southern Alaska. Interaction between the Yakutat terrane and the North American and Pacific plates causes significant differences in the style of deformation within the terrane. Deformation in the eastern part of the terrane is caused by strike-slip faulting along the Fairweather transform fault and by reverse faulting beneath the coastal mountains, but there is little deformation immediately offshore. The central part of the orogen is marked by thrusting of the Yakutat terrane beneath the North American plate along the Chugach–Saint Elias fault and development of a wide, thin-skinned fold-and-thrust belt. Strike-slip faulting in this segment may be localized in the hanging wall of the Chugach–Saint Elias fault, or dissipated by thrust faulting beneath a north-northeast–trending belt of active deformation that cuts obliquely across the eastern end of the fold-and-thrust belt. Superimposed folds with complex shapes and plunging hinge lines accommodate horizontal shortening and extension in the western part of the orogen, where the sedimentary cover of the Yakutat terrane is accreted into the upper plate of the Aleutian subduction zone. These three structural segments are separated by transverse tectonic boundaries that cut across the Yakutat terrane and also coincide with the courses of piedmont glaciers that flow from the topographic backbone of the Saint Elias Mountains onto the coastal plain. The Malaspina fault–Pamplona structural zone separates the eastern and central parts of the orogen and is marked by reverse faulting and folding. Onshore, most of this boundary is buried beneath the western or "Agassiz" lobe of the Malaspina piedmont glacier. The boundary between the central fold-and-thrust belt and western zone of superimposed folding lies beneath the middle and lower course of the Bering piedmont glacier. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.