First evidence for ultrahigh-pressure garnet peridotite in the North American Cordillera

Abstract

Research Article| February 01, 2005 First evidence for ultrahigh-pressure garnet peridotite in the North American Cordillera Jason M. MacKenzie; Jason M. MacKenzie 1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada Search for other works by this author on: GSW Google Scholar Dante Canil; Dante Canil 1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada Search for other works by this author on: GSW Google Scholar Stephen T. Johnston; Stephen T. Johnston 1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada Search for other works by this author on: GSW Google Scholar Joseph English; Joseph English 1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada Search for other works by this author on: GSW Google Scholar Mitchell G. Mihalynuk; Mitchell G. Mihalynuk 2Geological Survey Branch, Ministry of Energy and Mines, Victoria, British Columbia V8W 9N3, Canada Search for other works by this author on: GSW Google Scholar Brian Grant Brian Grant 2Geological Survey Branch, Ministry of Energy and Mines, Victoria, British Columbia V8W 9N3, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Jason M. MacKenzie 1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada Dante Canil 1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada Stephen T. Johnston 1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada Joseph English 1School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8W 3P6, Canada Mitchell G. Mihalynuk 2Geological Survey Branch, Ministry of Energy and Mines, Victoria, British Columbia V8W 9N3, Canada Brian Grant 2Geological Survey Branch, Ministry of Energy and Mines, Victoria, British Columbia V8W 9N3, Canada Publisher: Geological Society of America Received: 28 Jun 2004 Revision Received: 01 Oct 2004 Accepted: 06 Oct 2004 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2005) 33 (2): 105–108. https://doi.org/10.1130/G20958.1 Article history Received: 28 Jun 2004 Revision Received: 01 Oct 2004 Accepted: 06 Oct 2004 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jason M. MacKenzie, Dante Canil, Stephen T. Johnston, Joseph English, Mitchell G. Mihalynuk, Brian Grant; First evidence for ultrahigh-pressure garnet peridotite in the North American Cordillera. Geology 2005;; 33 (2): 105–108. doi: https://doi.org/10.1130/G20958.1 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 SocietyGeology Search Advanced Search Abstract Constraints on the thickness of mantle lithosphere involved in collisional orogenesis are fundamental for understanding the geodynamics of mountain building and the overall growth of continents by accretionary tectonics. Garnet peridotite and ultrahigh-pressure (UHP) crustal rocks provide such a constraint in many collisional orogens but have hitherto been unrecognized in western North America's Cordillera. Here we show the first evidence for exhumation of UHP (>2.8 GPa) garnet peridotite and eclogite and for deposition of these rocks as detritus in an Early Jurassic forearc basin (Laberge Group, Yukon Territory and British Columbia). Our results suggest that collision in this part of the North American Cordillera must have been thick skinned, involving a Proterozoic continental mass with a lithosphere >100 km (and possibly to 150 km) thick. Our discovery also provides insight into the vigor of uplift and erosion of deep-seated rocks in a nascent continental arc. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.