Ophiolitic source rocks for Taconic-age flysch: Trace-element evidence

Abstract

Research Article| November 01, 1984 Ophiolitic source rocks for Taconic-age flysch: Trace-element evidence RICHARD N. HISCOTT RICHARD N. HISCOTT 1Department of Earth Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X5, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information RICHARD N. HISCOTT 1Department of Earth Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X5, Canada Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1984) 95 (11): 1261–1267. https://doi.org/10.1130/0016-7606(1984)95<1261:OSRFTF>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation RICHARD N. HISCOTT; Ophiolitic source rocks for Taconic-age flysch: Trace-element evidence. GSA Bulletin 1984;; 95 (11): 1261–1267. doi: https://doi.org/10.1130/0016-7606(1984)95<1261:OSRFTF>2.0.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 SocietyGSA Bulletin Search Advanced Search Abstract Flysch generated along the Appalachian orogen during the Ordovician Taconic Orogeny ranges in age from late Arenig to early Caradoc (allochthonous flysch) and from late Llanvirn to Ashgill (autochthonous flysch). Sandstones in these units are dominantly lithic arenites, with a heavy mineral suite containing common to abundant Mg-rich chromite north of the Canada–United States border. The only reasonable sources for the chromite were the lower ultramafic units of obducted ophiolites.Trace-element analyses (Cr, Ni, V, Cu, Ti, Zr, Y) of flysch sandstones indicate a striking increase in Cr and Ni concentrations from the United States Appalachians to the Canadian Appalachians. In the United States units, Cr is in the range of 10 to 50 ppm; Canadian flysch units average an order of magnitude more Cr. These results suggest that ophiolite obduction either did not occur or was of minor importance during the Taconic Orogeny in the United States Appalachians.The difference in ophiolite abundance between the Canadian and United States Appalachians suggests a fundamental difference in tectonic style along the orogen, a feature that must be accommodated by plate-tectonic models. New models will probably need to consider both obliquity of subduction and geological complexity of the Ordovician collision zone in order to explain the spatial distribution of obducted ophiolite sheets. 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.