Magmatism and rift margin evolution: Evidence from northwest Australia

Abstract

Research Article| September 01, 1992 Magmatism and rift margin evolution: Evidence from northwest Australia John R. Hopper; John R. Hopper 1Lamont-Doherty Geological Observatory, Palisades, New York 10964-10902Department of Geological Sciences, Columbia University, New York, New York 10027 Search for other works by this author on: GSW Google Scholar John C. Mutter; John C. Mutter 1Lamont-Doherty Geological Observatory, Palisades, New York 10964-10902Department of Geological Sciences, Columbia University, New York, New York 10027 Search for other works by this author on: GSW Google Scholar Roger L. Larson; Roger L. Larson 3Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882 Search for other works by this author on: GSW Google Scholar Carolyn Z. Mutter Carolyn Z. Mutter 1Lamont-Doherty Geological Observatory, Palisades, New York 10964-1090 Search for other works by this author on: GSW Google Scholar Author and Article Information John R. Hopper 1Lamont-Doherty Geological Observatory, Palisades, New York 10964-10902Department of Geological Sciences, Columbia University, New York, New York 10027 John C. Mutter 1Lamont-Doherty Geological Observatory, Palisades, New York 10964-10902Department of Geological Sciences, Columbia University, New York, New York 10027 Roger L. Larson 3Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882 Carolyn Z. Mutter 1Lamont-Doherty Geological Observatory, Palisades, New York 10964-1090 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 (9): 853–857. https://doi.org/10.1130/0091-7613(1992)020<0853:MARMEE>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 John R. Hopper, John C. Mutter, Roger L. Larson, Carolyn Z. Mutter; Magmatism and rift margin evolution: Evidence from northwest Australia. Geology 1992;; 20 (9): 853–857. doi: https://doi.org/10.1130/0091-7613(1992)020<0853:MARMEE>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 Deep crustal seismic observations from northwest Australia demonstrate that the Cuvier margin is a volcanic passive margin that formed as Greater India rifted away from Australia in the Early Cretaceous. Formation of the Cuvier Basin and initial sea-floor spreading resulted in the emplacement of exceptionally thick oceanic crust, while contemporaneous spreading off the adjacent Exmouth Plateau formed normal-thickness oceanic crust. Crust of normal thickness was generated in the Cuvier Basin within 3-4 m.y. after spreading began. There is no evidence for hot-spot activity with the appropriate timing or in the appropriate spatial pattern to account for the difference in volcanism along the margin. We believe that rapid rifting of the Cuvier margin created strong lateral temperature gradients in the subjacent upper mantle at the time of breakup. This induced small-scale convection in the upper mantle that increased the rate of upwelling and, thus, the volume of melt generated by decompression partial melting. In turn, this resulted in a larger volume of magma at the initiation of sea-floor spreading, and thicker oceanic crust was initially emplaced. Rifting on the Exmouth Plateau happened over a much longer period of time, and no such convective partial melting occurred. The volume of melt associated with rifting was therefore entirely the result of passive upwelling, and a normal thickness of oceanic crust was emplaced immediately adjacent to the Exmouth Plateau. 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.