The Calderian orogeny in Wopmay orogen (1.9 Ga), northwestern Canadian Shield

Abstract

Research Article| May 01, 2010 The Calderian orogeny in Wopmay orogen (1.9 Ga), northwestern Canadian Shield Robert S. Hildebrand; Robert S. Hildebrand † 1Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85721, USA †e-mail: bob@roberthildebrand.com. Search for other works by this author on: GSW Google Scholar Paul F. Hoffman; Paul F. Hoffman § 2Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138, USA §Current address: School of Earth and Ocean Sciences, University of Victoria, Box 1700, Victoria, British Columbia V8W 2Y2, Canada. Search for other works by this author on: GSW Google Scholar Samuel A. Bowring Samuel A. Bowring 3Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Building 54-1126, Cambridge, Massachusetts 02139, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Robert S. Hildebrand † 1Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85721, USA Paul F. Hoffman § 2Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138, USA Samuel A. Bowring 3Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Building 54-1126, Cambridge, Massachusetts 02139, USA †e-mail: bob@roberthildebrand.com. §Current address: School of Earth and Ocean Sciences, University of Victoria, Box 1700, Victoria, British Columbia V8W 2Y2, Canada. Publisher: Geological Society of America Received: 20 Aug 2008 Revision Received: 10 Mar 2009 Accepted: 14 Apr 2009 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2010 Geological Society of America GSA Bulletin (2010) 122 (5-6): 794–814. https://doi.org/10.1130/B26521.1 Article history Received: 20 Aug 2008 Revision Received: 10 Mar 2009 Accepted: 14 Apr 2009 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Robert S. Hildebrand, Paul F. Hoffman, Samuel A. Bowring; The Calderian orogeny in Wopmay orogen (1.9 Ga), northwestern Canadian Shield. GSA Bulletin 2010;; 122 (5-6): 794–814. doi: https://doi.org/10.1130/B26521.1 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 Wopmay orogen is a Paleoproterozoic orogenic belt formed in part by the accretion of Hottah terrane, an east-facing continental magmatic arc, to the western margin of the Archean Slave craton at ca. 1.88 Ga. The arc-continent collision was responsible for the Calderian orogeny. Just prior to the collision, arc volcanism of the Hottah terrane had migrated trenchward and changed in composition from an aphyric calc-alkaline to a bimodal tholeiitic suite. The change in magmatism, along with subsidence and consequent high-temperature–low-pressure metamorphism of rocks on the upper plate, is attributed to extension and asthenospheric upwelling during rollback of the lower plate. The upwelling led to regional heating of the crust, melting, and generation of the metaluminous to peraluminous Hepburn intrusive suite within the arc just prior to accretion of Hottah terrane onto the Slave craton. During the collision, a 200-km-long, orogen-parallel swarm of mafic sills was intruded into the lower plate and trench-fill sediments at the passive-margin shelf-slope break. The mafic magmatism may have been induced by slab breakoff. The Calderian orogeny provides an excellent example of the magmatic history of an arc-continent collision.The Calderian orogeny was short-lived. Within a few million years, an east-dipping subduction zone formed outboard of the accreted terrane, creating volcanic rocks that were erupted atop the eroded Hottah-Slave collision zone. The short duration of the Calderian orogeny seems typical of arc-continent collisions, perhaps because the attenuated arc crust, coupled with the extended crust of the lower plate, never generates severely overthickened crust. Rise of asthenospheric mantle due to slab breakoff generates rapid uplift, erosion, and collapse of the mountains built during collision. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.