Detrital Avalonian zircons in the Laurentian Southern Uplands terrane, Scotland

Abstract

Research Article| July 01, 2003 Detrital Avalonian zircons in the Laurentian Southern Uplands terrane, Scotland E.R. Phillips; E.R. Phillips 1British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK Search for other works by this author on: GSW Google Scholar J.A. Evans; J.A. Evans 2Natural Environment Research Council Isotope Geosciences Laboratory, Keyworth, Nottingham NG12 5GG, UK Search for other works by this author on: GSW Google Scholar P. Stone; P. Stone 3British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK Search for other works by this author on: GSW Google Scholar M.S.A. Horstwood; M.S.A. Horstwood 4Natural Environment Research Council Isotope Geosciences Laboratory, Keyworth, Nottingham NG12 5GG, UK Search for other works by this author on: GSW Google Scholar J.D. Floyd; J.D. Floyd 5British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK Search for other works by this author on: GSW Google Scholar R.A. Smith; R.A. Smith 5British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK Search for other works by this author on: GSW Google Scholar M.C. Akhurst; M.C. Akhurst 5British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK Search for other works by this author on: GSW Google Scholar H.F. Barron H.F. Barron 5British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK Search for other works by this author on: GSW Google Scholar Author and Article Information E.R. Phillips 1British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK J.A. Evans 2Natural Environment Research Council Isotope Geosciences Laboratory, Keyworth, Nottingham NG12 5GG, UK P. Stone 3British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK M.S.A. Horstwood 4Natural Environment Research Council Isotope Geosciences Laboratory, Keyworth, Nottingham NG12 5GG, UK J.D. Floyd 5British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK R.A. Smith 5British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK M.C. Akhurst 5British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK H.F. Barron 5British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK Publisher: Geological Society of America Received: 06 Jan 2003 Revision Received: 25 Mar 2003 Accepted: 01 Apr 2003 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2003) 31 (7): 625–628. https://doi.org/10.1130/0091-7613(2003)031<0625:DAZITL>2.0.CO;2 Article history Received: 06 Jan 2003 Revision Received: 25 Mar 2003 Accepted: 01 Apr 2003 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation E.R. Phillips, J.A. Evans, P. Stone, M.S.A. Horstwood, J.D. Floyd, R.A. Smith, M.C. Akhurst, H.F. Barron; Detrital Avalonian zircons in the Laurentian Southern Uplands terrane, Scotland. Geology 2003;; 31 (7): 625–628. doi: https://doi.org/10.1130/0091-7613(2003)031<0625:DAZITL>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 SocietyGeology Search Advanced Search Abstract The Silurian–Ordovician Southern Uplands terrane occupies a key position in the Caledonian orogen, yet its genesis is controversial. Marginal-basin, backarc, and forearc tectonic regimes have all been invoked as operative at the Laurentian margin of the Iapetus Ocean. Fresh andesitic detritus within turbidite sandstones has, until now, been assumed to provide evidence for an Ordovician suprasubduction volcanic arc, a central feature of most models. However, high-precision thermal-ionization mass spectrometer U-Pb and laser-ablation data for detrital zircons from the sandstone prove Neoproterozoic volcanism at 557 ± 6 Ma (2σ) and probably also at 613 ± 12 Ma (2σ). The complex crystallization history recorded by the zircons shows assimilation of 1043 ± 7 Ma (2σ) Grenvillian basement into the andesite magma. The fact that no zircons have been found having ages that overlap the Caradocian depositional age of the host sedimentary rocks undermines all extant terrane models. The age profile of the detrital zircons is typical of Gondwana and Avalonia. This finding has important implications for the paleogeography of the Iapetus Ocean during the Ordovician, because the zircon data require the introduction of Avalonian detritus into a sedimentary basin marginal to Laurentia. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.