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Lithogeochemical and Sm-Nd and U-Pb isotope data from the Silurian–Lower Devonian Arisaig Group clastic rocks, Avalon terrane, Nova Scotia: A record of terrane accretion in the Appalachian-Caledonide orogen

2004; Geological Society of America; Volume: 116; Issue: 9 Linguagem: Inglês

10.1130/b25423.1

1943-2674

J. Brendan Murphy, Javier Fernández‐Suárez, Teresa E. Jeffries,

Geochemistry and Elemental Analysis

Research Article| September 01, 2004 Lithogeochemical and Sm-Nd and U-Pb isotope data from the Silurian–Lower Devonian Arisaig Group clastic rocks, Avalon terrane, Nova Scotia: A record of terrane accretion in the Appalachian-Caledonide orogen J. Brendan Murphy; J. Brendan Murphy 1Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia B2G 2W5, Canada Search for other works by this author on: GSW Google Scholar Javier Fernández-Suárez; Javier Fernández-Suárez 2Departamento de Petrología y Geoquímica, Universidad Complutense, 28040 Madrid, Spain Search for other works by this author on: GSW Google Scholar Teresa E. Jeffries Teresa E. Jeffries 3Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK Search for other works by this author on: GSW Google Scholar Author and Article Information J. Brendan Murphy 1Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia B2G 2W5, Canada Javier Fernández-Suárez 2Departamento de Petrología y Geoquímica, Universidad Complutense, 28040 Madrid, Spain Teresa E. Jeffries 3Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK Publisher: Geological Society of America Received: 14 Jun 2003 Revision Received: 21 Feb 2004 Accepted: 23 Feb 2004 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2004) 116 (9-10): 1183–1201. https://doi.org/10.1130/B25423.1 Article history Received: 14 Jun 2003 Revision Received: 21 Feb 2004 Accepted: 23 Feb 2004 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation J. Brendan Murphy, Javier Fernández-Suárez, Teresa E. Jeffries; Lithogeochemical and Sm-Nd and U-Pb isotope data from the Silurian–Lower Devonian Arisaig Group clastic rocks, Avalon terrane, Nova Scotia: A record of terrane accretion in the Appalachian-Caledonide orogen. GSA Bulletin 2004;; 116 (9-10): 1183–1201. doi: https://doi.org/10.1130/B25423.1 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 The Silurian–Lower Devonian Arisaig Group, in the Avalon terrane of Nova Scotia, consists of a thick (∼1900 m) sequence of unmetamorphosed fossiliferous siliciclastic strata deposited during terrane accretionary events in the Appalachian-Caledonide orogen. Geochemistry and Sm-Nd and U-Pb (detrital zircon) isotope data of Arisaig Group rocks contrast with the underlying Avalonian rocks, indicating that they were not derived from Avalonian basement. All sedimentary rocks are characterized by strongly negative ϵNd(t) values (from −4.8 to −9.3, t = 430 Ma) and TDM ages older than 1.5 Ga; the overall trend from the base to the top of the group is toward increasingly negative ϵNd values. The fact that some Silurian sedimentary rocks contain detrital zircons of similar age suggests that basin formation was broadly coeval with active volcanism in the orogen. These samples also contain abundant Neoproterozoic–Early Cambrian zircons (ca. 620–520 Ma) and lesser abundances at ca. 1200–900 and 2200–1500 Ma. Archean zircons are very minor. The sample of Lower Devonian strata contains Late Silurian and Early Ordovician zircons and, in comparison to the Silurian samples, less abundant Cambrian (ca. 520–510 Ma) and Neoproterozoic (610–550 Ma; 834 Ma) zircons and subordinate Mesoproterozoic (1000–1200 Ma), Mesoproterozoic (1400–1600 Ma), and Paleoproterozoic (2000–2100 Ma) zircons. There are no Archean zircons. A comparison between the U-Pb detrital-zircon data and the age of tectonothermal events in potential source areas, together with regional geologic data, suggests that Silurian strata of the Arisaig Group were primarily derived from Baltica, but that there was increasing input from Laurentia by the time of deposition of the Lower Devonian strata of the group. The Arisaig Group is interpreted to have been deposited adjacent to the trailing edge of Avalonia during Appalachian accretionary events, and the geochemical and isotopic characteristics of its strata clearly record the signatures of these regional tectonic events. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.