Timing of tectonometamorphism across the Green Mountain anticlinorium, northern Vermont Appalachians: 40Ar/39Ar data and correlations with southern Quebec

Research Article| March 01, 2012 Timing of tectonometamorphism across the Green Mountain anticlinorium, northern Vermont Appalachians: 40Ar/39Ar data and correlations with southern Quebec Sébastien Castonguay; Sébastien Castonguay † 1Geological Survey of Canada, 940 rue de la Couronne, Québec, Québec G1K 9A9, Canada †E-mail: sebastien.castonguay@nrcan.gc.ca Search for other works by this author on: GSW Google Scholar Jonathan Kim; Jonathan Kim 2Vermont Geological Survey, 103 South Main Street, Logue Cottage, Waterbury, Vermont 05671-2420, USA Search for other works by this author on: GSW Google Scholar Peter J. Thompson; Peter J. Thompson 3Department of Earth Sciences, University of New Hampshire, Durham, New Hampshire 03824, USA Search for other works by this author on: GSW Google Scholar Marjorie H. Gale; Marjorie H. Gale 2Vermont Geological Survey, 103 South Main Street, Logue Cottage, Waterbury, Vermont 05671-2420, USA Search for other works by this author on: GSW Google Scholar Nancy Joyce; Nancy Joyce 4Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada Search for other works by this author on: GSW Google Scholar Jo Laird; Jo Laird 3Department of Earth Sciences, University of New Hampshire, Durham, New Hampshire 03824, USA Search for other works by this author on: GSW Google Scholar Barry L. Doolan Barry L. Doolan 5Department of Geology, University of Vermont, Burlington, Vermont 05405, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2012) 124 (3-4): 352–367. https://doi.org/10.1130/B30487.1 Article history received: 01 Feb 2011 rev-recd: 08 Jun 2011 accepted: 03 Jul 2011 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 Sébastien Castonguay, Jonathan Kim, Peter J. Thompson, Marjorie H. Gale, Nancy Joyce, Jo Laird, Barry L. Doolan; Timing of tectonometamorphism across the Green Mountain anticlinorium, northern Vermont Appalachians: 40Ar/39Ar data and correlations with southern Quebec. GSA Bulletin 2012;; 124 (3-4): 352–367. doi: https://doi.org/10.1130/B30487.1 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 pre-Silurian lithotectonic units of the northern Vermont Appalachians, the timing of orogenesis and tectonometamorphism has traditionally been ascribed to the combined effects of the Middle Ordovician Taconian orogeny and Middle to Late Devonian Acadian orogeny. However, numerous geochronological studies throughout the Northern Appalachians, including neighboring southern Quebec, have obtained Silurian and Early Devonian age data that document more or less continuous tectonometamorphic activity throughout the Ordovician–Devonian. The structural and metamorphic evolution of northern Vermont can be separated into three regional phases, which are characterized by distinct structures, fabrics, and metamorphic parageneses. The first phase (D1), associated with westward emplacement of various thrust slices leading to crustal thickening and regional metamorphism, and the second phase (D2), characterized by bivergent structures and metamorphic overprint, have both been considered to be Taconian. The third phase, the structure and fabric of which are also observed in the Silurian–Devonian rocks to the east, is considered to be Acadian. We present new step-heating and spot fusion 40Ar/39Ar geochronological data on amphibole and fabric-forming muscovite from samples taken across the Green Mountain anticlinorium, which, coupled with published data, provide improved age constraints on tectonometamorphism of D1 (latest Cambrian to Middle Ordovician), D2 (Silurian–Early Devonian), and D3 (Middle Devonian) events. By comparing structural and metamorphic characteristics, and now timing, these phases are interpreted to be correlative to the tripartite tectonometamorphic evolution documented in southern Quebec, and they further exemplify the along-strike diachronism of tectonism induced by the inherited irregular geometry of the Laurentian margin. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.