Neoproterozoic continental arc magmatism in west-central Madagascar

Abstract

Research Article| April 01, 1999 Neoproterozoic continental arc magmatism in west-central Madagascar Michael J. Handke; Michael J. Handke 1Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130-4899, USA Search for other works by this author on: GSW Google Scholar Robert D. Tucker; Robert D. Tucker 1Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130-4899, USA Search for other works by this author on: GSW Google Scholar Lewis D. Ashwal Lewis D. Ashwal 2Department of Geology, Rand Afrikaans University, Auckland Park, 2006, South Africa Search for other works by this author on: GSW Google Scholar Author and Article Information Michael J. Handke 1Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130-4899, USA Robert D. Tucker 1Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130-4899, USA Lewis D. Ashwal 2Department of Geology, Rand Afrikaans University, Auckland Park, 2006, South Africa Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1999) 27 (4): 351–354. https://doi.org/10.1130/0091-7613(1999)027<0351:NCAMIW>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 Michael J. Handke, Robert D. Tucker, Lewis D. Ashwal; Neoproterozoic continental arc magmatism in west-central Madagascar. Geology 1999;; 27 (4): 351–354. doi: https://doi.org/10.1130/0091-7613(1999)027<0351:NCAMIW>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 Published geologic maps, regional geological relations, and new U-Pb ages for intrusive igneous rocks in west-central Madagascar define a 450-km-long belt of rocks emplaced in middle Neoproterozoic time. We report precise U-Pb zircon and baddeleyite ages for 11 coeval gabbro and granitoid plutons from the Itremo region, located in the southern part of this belt. The ages for all gabbroic and granitic plutons and deformed equivalents define an ∼25 m.y. period of magmatic activity between 804 and 779 Ma (at maximum uncertainty). Granitoids intrusive into the Quartzo-Schisto-Calcaire series provide a minimum depositional age of 791 Ma for this Mesoproterozoic platformal sedimentary sequence. Our results, combined with other recent U-Pb age determinations, define a belt of plutonic rocks in west-central Madagascar emplaced between 804 and 776 Ma. We propose that these middle Neoproterozoic rocks constitute the root of a continental magmatic arc emplaced at the time of, or slightly preceding, the breakup of the Rodinian supercontinent. Neoproterozoic plate reconstructions place Madagascar on the putative margin of Rodinia, and therefore the plutonic belt in west-central Madagascar provides important constraints on the timing and extent of middle Neoproterozoic tectonic events in Rodinia and the critical period of Rodinia's transformation into Gondwana. 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.