Supercontinent model for the contrasting character of Late Proterozoic orogenic belts

Abstract

Research Article| May 01, 1991 Supercontinent model for the contrasting character of Late Proterozoic orogenic belts J. Brendan Murphy; J. Brendan Murphy 1Department of Geology, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 1CO, Canada Search for other works by this author on: GSW Google Scholar R. Damian Nance R. Damian Nance 2Department of Geological Sciences, Ohio University, Athens, Ohio 45701 Search for other works by this author on: GSW Google Scholar Author and Article Information J. Brendan Murphy 1Department of Geology, St. Francis Xavier University, Antigonish, Nova Scotia, B2G 1CO, Canada R. Damian Nance 2Department of Geological Sciences, Ohio University, Athens, Ohio 45701 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 (5): 469–472. https://doi.org/10.1130/0091-7613(1991)019<0469:SMFTCC>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 Email Permissions Search Site Citation J. Brendan Murphy, R. Damian Nance; Supercontinent model for the contrasting character of Late Proterozoic orogenic belts. Geology 1991;; 19 (5): 469–472. doi: https://doi.org/10.1130/0091-7613(1991)019<0469:SMFTCC>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 Two fundamentally different types of orogenic belts may reflect the accretion and breakup of a Late Proterozoic supercontinent. Interior orogens (e.g., trans- Saharan fold belts) lie within the supercontinent after its amalgamation. Orogenic activity commenced with ca. 850-800 Ma Cordilleran-type subduction associated with contraction of interior oceans and terminated in ca. 650-600 Ma continent-continent collision and the amalgamation of an Afro-Brazilian supercontinent. Orogenic activity produced abundant calc-alkalic granitoid magmatism, crustal thickening, large-scale thrusting, uplift and exposure of medium-to high-grade metamorphic rocks, and regional angular unconformities with postorogenic sequences. In contrast, peripheral orogens (e.g., Avalonian-Cadomian belt, Arabian shield) lie at the extremity of the supercontinent following its amalgamation. Orogenic activity commenced with ca. 820-800 Ma subduction in an exterior, expanding ocean that generated a diverse assemblage of arcs and back-arc basins as the plate retreated from the subducting slab. Voluminous ca. 600 Ma ensialic tectonothermal activity in peripheral orogens may reflect renewed subduction at the periphery of the supercontinent following its amalgamation and the destruction of interior oceans. Peripheral orogenic activity produced synorogenic, low-grade volcanic-sedimentary successions, inter-arc and intra-arc rifts, localized and predominantly strike-slip deformation, limited uplift, and only local unconformities with postorogenic successions. Basin closure and termination of peripheral orogens may reflect supercontinent breakup and dispersal. 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.