Oxygen isotope geochemistry of the silicic volcanic rocks of the Etendeka-Paraná province: Source constraints

Abstract

Research Article| November 01, 1990 Oxygen isotope geochemistry of the silicic volcanic rocks of the Etendeka-Paraná province: Source constraints Chris Harris; Chris Harris 1Department of Geochemistry, University of Cape Town, Rondebosch 7700 South Africa Search for other works by this author on: GSW Google Scholar Andrew M. Whittingham; Andrew M. Whittingham 2Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, England Search for other works by this author on: GSW Google Scholar Simon C. Milner; Simon C. Milner 1Department of Geochemistry, University of Cape Town, Rondebosch 7700 South Africa Search for other works by this author on: GSW Google Scholar Richard A. Armstrong Richard A. Armstrong 1Department of Geochemistry, University of Cape Town, Rondebosch 7700 South Africa Search for other works by this author on: GSW Google Scholar Author and Article Information Chris Harris 1Department of Geochemistry, University of Cape Town, Rondebosch 7700 South Africa Andrew M. Whittingham 2Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, England Simon C. Milner 1Department of Geochemistry, University of Cape Town, Rondebosch 7700 South Africa Richard A. Armstrong 1Department of Geochemistry, University of Cape Town, Rondebosch 7700 South Africa Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1990) 18 (11): 1119–1121. https://doi.org/10.1130/0091-7613(1990)018<1119:OIGOTS>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 Chris Harris, Andrew M. Whittingham, Simon C. Milner, Richard A. Armstrong; Oxygen isotope geochemistry of the silicic volcanic rocks of the Etendeka-Paraná province: Source constraints. Geology 1990;; 18 (11): 1119–1121. doi: https://doi.org/10.1130/0091-7613(1990)018<1119:OIGOTS>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 Oxygen isotope ratios of pyroxene phenocrysts in the silicic volcanic rocks from the Cretaceous Etendeka-Paraná flood basalt province (Namibia, South America) are believed to reflect the δ18O values of the original magmas. We recognize a high δ18O value type (δ18O pyroxene ∼+10‰) found in the south of both regions, and a low δ18O value type (δ18O pyroxene ∼ +6.5‰) found in the north. Other differences between these two rhyolite types include higher concentrations of incompatible elements and lower initial 87Sr/86Sr ratios in the low δ18O value type. We suggest that the regional distribution of rhyolite types reflects differences in source composition, which can best be explained if the sources are lower crustal, Late Proterozoic mobile belt material (high δ18O) and Archean lower crust (low δ18O). 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.