Inhibiting magmatism on nonvolcanic rifted margins

Abstract

Research Article| October 01, 1999 Inhibiting magmatism on nonvolcanic rifted margins D. L. Harry; D. L. Harry 1Department of Geology, University of Alabama, Box 870338, Tuscaloosa, Alabama 35487-0338, USA Search for other works by this author on: GSW Google Scholar J. C. Bowling J. C. Bowling 1Department of Geology, University of Alabama, Box 870338, Tuscaloosa, Alabama 35487-0338, USA Search for other works by this author on: GSW Google Scholar Author and Article Information D. L. Harry 1Department of Geology, University of Alabama, Box 870338, Tuscaloosa, Alabama 35487-0338, USA J. C. Bowling 1Department of Geology, University of Alabama, Box 870338, Tuscaloosa, Alabama 35487-0338, USA Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1999) 27 (10): 895–898. https://doi.org/10.1130/0091-7613(1999)027<0895:IMONRM>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 D. L. Harry, J. C. Bowling; Inhibiting magmatism on nonvolcanic rifted margins. Geology 1999;; 27 (10): 895–898. doi: https://doi.org/10.1130/0091-7613(1999)027<0895:IMONRM>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 The conditions under which continental rifting may occur without an accompanying protracted period of synextensional magmatism are explored with a series of finite element models that dynamically simulate continental extension. The models demonstrate that 5–7 km of new oceanic crust can be generated at the time of breakup while restricting synextensional magmatism to less than 2 m.y. prior to the end of the rifting episode if the extension rate exceeds ∼15 mm/yr and the crust contains only minor lateral variations in strength. Under these conditions, extensional strain in the mantle is localized during the early stages of rifting, preventing diffuse lithospheric thinning. Melting does not begin until lithospheric necking is well established, resulting in a narrow zone of melt production that limits magmatism to within ∼30 km of the ocean-continent boundary. Once melting begins, rifting progresses rapidly to breakup, restricting the period of synextensional magmatism to as little as 1.6 m.y. prior to the onset of sea-floor spreading. Because the models do not require either a cool mantle prior to rifting or pronounced conductive cooling of the mantle during rifting, they are able to account for the generation of new oceanic crust at the time of breakup. The model predictions are consistent with the structure and magmatic history of nonvolcanic rifted margins in the North Atlantic Ocean. 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.