The Annieopsquotch ophiolite belt of southwest Newfoundland: Geology and tectonic significance

Abstract

Research Article| November 01, 1985 The Annieopsquotch ophiolite belt of southwest Newfoundland: Geology and tectonic significance G. R. DUNNING; G. R. DUNNING 1Department of Mineralogy and Geology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada Search for other works by this author on: GSW Google Scholar L. B. CHORLTON L. B. CHORLTON 2Ontario Geological Survey, Mineral Deposits Branch, 77 Grenville Street, Toronto, Ontario M5S 1B3, Canada Search for other works by this author on: GSW Google Scholar GSA Bulletin (1985) 96 (11): 1466–1476. https://doi.org/10.1130/0016-7606(1985)96<1466:TAOBOS>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 MailTo Tools Icon Tools Get Permissions Search Site Citation G. R. DUNNING, L. B. CHORLTON; The Annieopsquotch ophiolite belt of southwest Newfoundland: Geology and tectonic significance. GSA Bulletin 1985;; 96 (11): 1466–1476. doi: https://doi.org/10.1130/0016-7606(1985)96<1466:TAOBOS>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 The Annieopsquotch ophiolite belt consists of ophiolite fragments exposed from Buchans in central Newfoundland to the southwest tip of the island. The largest remnants belong to the Annieopsquotch Complex in the northeast and the Long Range Mafic-Ultramafic Complex in the southwest. The Arenigian Annieopsquotch Complex exposes an ophiolite stratigraphy from layered cumulate gabbro (Moho sequence) through high-level gabbro, sheeted dikes, pillow lava, and chert. The Long Range Mafic-Ultramafic Complex consists largely of cumulate and high-level metagabbro with subordinate ultramafic rock and metabasalt, all engulfed as massif- to xenolith-size fragments in Ordovician tonalitic and younger mafic to felsic granitoid intrusions. The latter rocks are intersected by a wide, locally gently inclined, high-temperature ductile thrust zone, which also encompasses amphibolite, semipelitic schist, and marble. Between Buchans and the southwest tip of Newfoundland, the tonalite terrane encloses many smaller ophiolitic fragments. The ophiolite fragments of the northern half of the belt have similar dike trends, have N-type MORB chemistry, and likely formed one major allochthon of Iapetus oceanic crust. This was disrupted by the intrusion of tonalite and other magmas in an arc or arc-trench environment and by subsequent faulting. An attempt is made to assess the significance of the Annieopsquotch belt in relation to ether Newfoundland ophiolites. 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.