Opening Iapetus: Constraints from the Laurentian margin in Newfoundland

Abstract

Research Article| April 01, 2001 Opening Iapetus: Constraints from the Laurentian margin in Newfoundland Peter A. Cawood; Peter A. Cawood 1Tectonics Special Research Centre, School of Applied Geology, Curtin University, GPO Box U1987, Perth 6845, Australia Search for other works by this author on: GSW Google Scholar Phil J.A. McCausland; Phil J.A. McCausland 2Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B7, Canada Search for other works by this author on: GSW Google Scholar Greg R. Dunning Greg R. Dunning 3Department of Earth Sciences, Memorial University, St. John's, Newfoundland A1B 3X5, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Peter A. Cawood 1Tectonics Special Research Centre, School of Applied Geology, Curtin University, GPO Box U1987, Perth 6845, Australia Phil J.A. McCausland 2Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B7, Canada Greg R. Dunning 3Department of Earth Sciences, Memorial University, St. John's, Newfoundland A1B 3X5, Canada Publisher: Geological Society of America Received: 27 Oct 1999 Revision Received: 10 Apr 2000 Accepted: 09 May 2000 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2001) 113 (4): 443–453. https://doi.org/10.1130/0016-7606(2001)113<0443:OICFTL>2.0.CO;2 Article history Received: 27 Oct 1999 Revision Received: 10 Apr 2000 Accepted: 09 May 2000 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 Peter A. Cawood, Phil J.A. McCausland, Greg R. Dunning; Opening Iapetus: Constraints from the Laurentian margin in Newfoundland. GSA Bulletin 2001;; 113 (4): 443–453. doi: https://doi.org/10.1130/0016-7606(2001)113<0443:OICFTL>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 Late Neoproterozoic to Early Cambrian geologic, geochronologic, and paleomagnetic data from along the Iapetus margin of Laurentia may be reconciled within a multistage rift history that involved an initial separation of Laurentia from the west Gondwana cratons ca. 570 Ma, followed by rifting of a further block or blocks from Laurentia ca. 540– 535 Ma into an already open Iapetus Ocean to establish the main passive-margin sequence in the Appalachians. Paleomagnetic data suggest that Laurentia rifted from Amazonia−Rio de la Plata cratons and began its northward movement ca. 570 Ma to produce a wide Iapetus Ocean by 550 Ma. Geologic data from the Newfoundland segment of the Laurentian margin provide evidence for a rift-drift transition ca. 540–535 Ma, as constrained by the youngest rift-related magmatism at 550.5 +3/–2 Ma (U/Pb zircon) for the Skinner Cove Formation and 555 +3/–5 Ma for the Lady Slipper pluton, and a late Early Cambrian age of ca. 525–520 Ma for the oldest drift-related sedimentation. Rifting between the Laurentia and the west Gondwana cratons was probably distributed among multiple rift systems that fostered the production of a number of terranes (such as the Argentine Precordillera, Oaxacan) as well as the Iapetus Ocean. Development of Laurentian-derived Iapetan terranes during the final breakout of Laurentia from Rodinia may have been facilitated by preexisting 760–700 Ma rift weaknesses and apparently rapidly changing plate vectors during latest Neoproterozoic time. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.