Volcanic arc emplacement onto the southernmost Appalachian Laurentian shelf: Characteristics and constraints

Abstract

Research Article| March 01, 2007 Volcanic arc emplacement onto the southernmost Appalachian Laurentian shelf: Characteristics and constraints James F. Tull; James F. Tull 1Department of Geological Sciences, Florida State University, Tallahassee, Florida 32306, USA Search for other works by this author on: GSW Google Scholar Clinton I. Barineau; Clinton I. Barineau 1Department of Geological Sciences, Florida State University, Tallahassee, Florida 32306, USA Search for other works by this author on: GSW Google Scholar Paul A. Mueller; Paul A. Mueller 2Department of Geological Sciences, University of Florida, Gainesville, Florida 32611, USA Search for other works by this author on: GSW Google Scholar Joseph L. Wooden Joseph L. Wooden 3U.S. Geological Survey, MS 937, Menlo Park, California 94050, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2007) 119 (3-4): 261–274. https://doi.org/10.1130/B25998.1 Article history received: 07 Mar 2006 rev-recd: 08 Sep 2006 accepted: 14 Oct 2006 first online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation James F. Tull, Clinton I. Barineau, Paul A. Mueller, Joseph L. Wooden; Volcanic arc emplacement onto the southernmost Appalachian Laurentian shelf: Characteristics and constraints. GSA Bulletin 2007;; 119 (3-4): 261–274. doi: https://doi.org/10.1130/B25998.1 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 the southernmost Appalachians, the Hillabee Greenstone, an Ordovician volcanic arc fragment, lies directly atop the outermost Laurentian Devonian–earliest Mississippian(?) shelf sequence at the structural top of the greenschist facies Talladega belt, the frontal metamorphic allochthon along this orogenic segment. The Hillabee Greenstone was emplaced between latest Devonian and middle Mississippian time. It and the uppermost Laurentian section were later repeated together within a series of map-scale imbricate slices of a postmetamorphic, dextral, transpressional, Alleghanian thrust duplex system that placed the high-grade eastern Blue Ridge allochthon atop the Talladega belt. Geochemical and geochronologic (U-Pb zircon) studies indicate that the Hillabee Greenstone's interstratified tholeiitic meta-basalt and calc-alkaline metadacite/rhyolite formed within an extensional setting on continental crust ca. 460–470 Ma. Palinspastic reconstructions of the southern Appalachian Ordovician margin place the Hillabee Greenstone outboard of the present position of the Pine Mountain terrane and suggest links to Ordovician plutonism in the overlying eastern Blue Ridge, and possibly to widespread K-bentonite deposits within Ordovician platform units. The tectonic evolution of the Hillabee Greenstone exhibits many unusual and intriguing features, including: (1) premeta-morphic emplacement along a basal cryptic thrust, which is remarkably concordant to both hanging wall and footwall sequences across its entire extent (>230 km), (2) formation, transport, and emplacement of the arc fragment accompanied by minimal deformation of the Hillabee Greenstone and underlying outer-margin shelf rocks, (3) emplacement temporally coincident with the adjacent collision of the younger, tectonically independent Ouachita volcanic arc with southeastern Laurentia. These features highlight strong contrasts in the Ordovician-Taconian evolution of the southern and northern parts of the Appalachian orogen. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.