A mechanism for construction of volcanic rifted margins during continental breakup

Abstract

Research Article| December 01, 2014 A mechanism for construction of volcanic rifted margins during continental breakup David G. Quirk; David G. Quirk Maersk Oil, Esplanaden 50, 1263 Copenhagen K, Denmark Search for other works by this author on: GSW Google Scholar Alaister Shakerley; Alaister Shakerley Maersk Oil, Esplanaden 50, 1263 Copenhagen K, Denmark Search for other works by this author on: GSW Google Scholar Matthew J. Howe Matthew J. Howe Maersk Oil, Esplanaden 50, 1263 Copenhagen K, Denmark Search for other works by this author on: GSW Google Scholar Author and Article Information David G. Quirk Maersk Oil, Esplanaden 50, 1263 Copenhagen K, Denmark Alaister Shakerley Maersk Oil, Esplanaden 50, 1263 Copenhagen K, Denmark Matthew J. Howe Maersk Oil, Esplanaden 50, 1263 Copenhagen K, Denmark Publisher: Geological Society of America Received: 10 Jun 2014 Revision Received: 16 Sep 2014 Accepted: 29 Sep 2014 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2014 Geological Society of America Geology (2014) 42 (12): 1079–1082. https://doi.org/10.1130/G35974.1 Article history Received: 10 Jun 2014 Revision Received: 16 Sep 2014 Accepted: 29 Sep 2014 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation David G. Quirk, Alaister Shakerley, Matthew J. Howe; A mechanism for construction of volcanic rifted margins during continental breakup. Geology 2014;; 42 (12): 1079–1082. doi: https://doi.org/10.1130/G35974.1 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 Research into the breakup of continents and formation of ocean basins has advanced in recent years, with deep-marine seismic data providing much of the impetus for new concepts. Attention has been focused on nonvolcanic (magma poor) margins; meanwhile, a satisfactory explanation for volcanic (magmatic) margins with their distinctive seaward-dipping reflectors (SDRs) has been missing. SDRs are composed of subaerial lava flows of tholeiitic basalt erupted during the transition from continental rifting to seafloor spreading, when the crust is both stretched and constructed from asthenosphere-derived magma. Here we present remarkable seismic images down to 40 km offshore East Greenland, showing that a newly described type of extensional fault plays an integral part in the ascent of magma and the building of transitional crust. Two such faults define an axial horst block supported by rising magma where the plates separate. Lava collects in seaward-growing half graben on either side of the horst, while new gabbroic crust is accreted along the flanks of the magma chamber in dilational shear zones beneath where the faults detach. Ultimately, rising asthenosphere reaches the base of the magma chamber, causing the horst to split, thereby initiating seafloor spreading. The model we describe shows how extension and magmatism interact at the boundaries of rifting plates. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.