SHRIMP U-Pb geochronology of Neoproterozoic Windermere Supergroup, central Idaho: Implications for rifting of western Laurentia and synchroneity of Sturtian glacial deposits

Abstract

Research Article| March 01, 2003 SHRIMP U-Pb geochronology of Neoproterozoic Windermere Supergroup, central Idaho: Implications for rifting of western Laurentia and synchroneity of Sturtian glacial deposits Karen Lund; Karen Lund 1U.S. Geological Survey, Denver, Colorado 80225, USA Search for other works by this author on: GSW Google Scholar John N. Aleinikoff; John N. Aleinikoff 1U.S. Geological Survey, Denver, Colorado 80225, USA Search for other works by this author on: GSW Google Scholar Karl V. Evans; Karl V. Evans 1U.S. Geological Survey, Denver, Colorado 80225, USA Search for other works by this author on: GSW Google Scholar C. Mark Fanning C. Mark Fanning 2Australian National University, Canberra, ACT 0200, Australia Search for other works by this author on: GSW Google Scholar GSA Bulletin (2003) 115 (3): 349–372. https://doi.org/10.1130/0016-7606(2003)115<0349:SUPGON>2.0.CO;2 Article history received: 14 Feb 2002 rev-recd: 21 Jun 2002 accepted: 20 Aug 2002 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 Karen Lund, John N. Aleinikoff, Karl V. Evans, C. Mark Fanning; SHRIMP U-Pb geochronology of Neoproterozoic Windermere Supergroup, central Idaho: Implications for rifting of western Laurentia and synchroneity of Sturtian glacial deposits. GSA Bulletin 2003;; 115 (3): 349–372. doi: https://doi.org/10.1130/0016-7606(2003)115<0349:SUPGON>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 In central Idaho roof pendants, a northwest-trending belt of metamorphosed strata, correlative with the Windermere Supergroup, links northern and southern segments of the western Laurentia Neoproterozoic rift belt. Nine newly named formations within the Gospel Peaks sequence-A through Gospel Peaks sequence-D record Cryogenian preglacial, rift-glacial, and postglacial events as well as Neoproterozoic III glacial and rift events. The Edwardsburg Formation of Gospel Peaks sequence B includes interfingered bimodal rift-related volcanic and glaciogenic diamictite strata. Zircons from a rhyodacite flow in the lower Edwardsburg Formation and from a rhyolite flow at its top, dated by using the sensitive high-resolution ion microprobe (SHRIMP), yielded a weighted average of 685 ± 7 Ma and 684 ± 4 Ma. Reevaluation of geochronology and correlations indicates that Cryogenian rifting may have been (1) protracted between 780 and 685 Ma, (2) diachronous along the Cordillera, and/or (3) stepwise with a Cordilleran-wide event at ca. 685 Ma that initiated the formation of the Cordilleran miogeocline and set its geometry. Reevaluation of the Cryogenian glacial record indicates that (1) two associated ca. 685 Ma glacial intervals in the Edwardsburg Formation correlate with the Rapitan glaciation, (2) the Sturtian snowball Earth event must be reevaluated on the basis of revision of Rapitan glaciation from 750–700 Ma to ca. 685 Ma, and (3) there were older Cryogenian glaciations or Cryogenian glaciations were not globally synchronous. New dates and correlations significantly impact the number and synchroneity of possible snowball Earth events and the paleolatitudes of Cryogenian glaciations. Western Laurentian events at ca. 685 Ma particularily affect Neoproterozoic paleocontinental reconstructions by indicating diachronous and multi step breakup of supercontinent Rodinia. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.