Pacific margins of Laurentia and East Antarctica-Australia as a conjugate rift pair: Evidence and implications for an Eocambrian supercontinent

Abstract

Research Article| June 01, 1991 Pacific margins of Laurentia and East Antarctica-Australia as a conjugate rift pair: Evidence and implications for an Eocambrian supercontinent Ian W.D. Dalziel Ian W.D. Dalziel 1Institute for Geophysics, University of Texas, 8701 Mopac Boulevard, Austin, Texas 78759 Search for other works by this author on: GSW Google Scholar Author and Article Information Ian W.D. Dalziel 1Institute for Geophysics, University of Texas, 8701 Mopac Boulevard, Austin, Texas 78759 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1991) 19 (6): 598–601. https://doi.org/10.1130/0091-7613(1991)019<0598:PMOLAE>2.3.CO;2 Article history First Online: 02 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 Ian W.D. Dalziel; Pacific margins of Laurentia and East Antarctica-Australia as a conjugate rift pair: Evidence and implications for an Eocambrian supercontinent. Geology 1991;; 19 (6): 598–601. doi: https://doi.org/10.1130/0091-7613(1991)019<0598:PMOLAE>2.3.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 SocietyGeology Search Advanced Search Abstract Evidence supports the hypothesis that the Laurentian and East Antarctic-Australian cratons were continuous in the late Precambrian and that their Pacific margins formed as a conjugate rift pair. Both margins extend for approximately 40° of latitude. They have a similar rift history throughout their length—i.e., Late Proterozoic rifting and Early Cambrian carbonate platform development. A geometrically acceptable computer-generated reconstruction for the latest Precambrian juxtaposes and aligns the Grenville front that is truncated at the Pacific margin of Laurentia and a closely comparable tectonic boundary in East Antarctica that is truncated along the Weddell Sea margin. These may prove to be critical, perhaps even unique, "piercing points" for relating the northern and southern continents. Geologic and paleomagnetic evidence also suggests that the Atlantic margin of Laurentia rifted from the proto-Andean margin of South America in earliest Cambrian time. Early Phanerozoic sea-floor spreading that isolated Laurentia from South America and East Antarctica-Australia in an Eocambrian supercontinent appears to balance convergence along the Mozambique suture which resulted in final amalgamation of the smaller Gondwana supercontinent at ∼500 Ma. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.