530 Ma zircon age for ophiolite from the New England orogen: Oldest rocks known from eastern Australia

Abstract

Research Article| February 01, 1992 530 Ma zircon age for ophiolite from the New England orogen: Oldest rocks known from eastern Australia J. C. Aitchison; J. C. Aitchison 1Department of Geology and Geophysics, University of Sydney, Sydney, New South Wales 2006, Australia Search for other works by this author on: GSW Google Scholar T. R. Ireland; T. R. Ireland 2Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia Search for other works by this author on: GSW Google Scholar M. C. Blake, Jr.; M. C. Blake, Jr. 3U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar P. G. Flood P. G. Flood 4Department of Geology and Geophysics, University of New England, Armidale, New South Wales 2351, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information J. C. Aitchison 1Department of Geology and Geophysics, University of Sydney, Sydney, New South Wales 2006, Australia T. R. Ireland 2Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia M. C. Blake, Jr. 3U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 P. G. Flood 4Department of Geology and Geophysics, University of New England, Armidale, New South Wales 2351, Australia Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1992) 20 (2): 125–128. https://doi.org/10.1130/0091-7613(1992)020<0125:MZAFOF>2.3.CO;2 Article history First Online: 02 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 J. C. Aitchison, T. R. Ireland, M. C. Blake, P. G. Flood; 530 Ma zircon age for ophiolite from the New England orogen: Oldest rocks known from eastern Australia. Geology 1992;; 20 (2): 125–128. doi: https://doi.org/10.1130/0091-7613(1992)020<0125:MZAFOF>2.3.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 New ion microprobe data provide constraints on the timing of formation of ophiolitic rocks in the New England tectonic collage in eastern Australia. Results for analyses of magmatic zircons from plagiogranite of the Weraerai terrane ophiolite at Upper Bingara give a 206Pb/238U age of 530 ±6 Ma (2σ). This plagiogranite is the oldest rock from eastern Australia yet identified. Existing tectonic models suggest that progressively younger crust was accreted to the eastern margin of Gondwanan Australia throughout the Paleozoic. This cannot be reconciled easily with the Cambrian age for these ophiolitic rocks, which are juxtaposed between Devonian terranes and are at least 1000 km east of the nearest lithologically similar rocks of comparable age. We speculate that younger, thin-skinned terranes may have been thrust westward over the continental freeboard of eastern Australia during the late Paleozoic. 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.