Three-dimensional seismic imaging of a protoridge axis in the Main Ethiopian rift

Abstract

Research Article| November 01, 2004 Three-dimensional seismic imaging of a protoridge axis in the Main Ethiopian rift K. Keranen; K. Keranen 1Department of Geophysics, Stanford University, Stanford, California 94305-2215, USA Search for other works by this author on: GSW Google Scholar S.L. Klemperer; S.L. Klemperer 1Department of Geophysics, Stanford University, Stanford, California 94305-2215, USA Search for other works by this author on: GSW Google Scholar R. Gloaguen; R. Gloaguen 2Department of Geology, TU “Bergakademie” Freiberg, B. von Cotta 2, 09599 Freiberg, Germany Search for other works by this author on: GSW Google Scholar EAGLE Working Group EAGLE Working Group 3EAGLE Working Group includes L. Asfaw, A. Ayele, C. Ebinger, T. Furman, S. Harder, G.R. Keller, G.D. Mackenzie, P.K.H. Maguire, and G.W. Stuart Search for other works by this author on: GSW Google Scholar Author and Article Information K. Keranen 1Department of Geophysics, Stanford University, Stanford, California 94305-2215, USA S.L. Klemperer 1Department of Geophysics, Stanford University, Stanford, California 94305-2215, USA R. Gloaguen 2Department of Geology, TU “Bergakademie” Freiberg, B. von Cotta 2, 09599 Freiberg, Germany EAGLE Working Group 3EAGLE Working Group includes L. Asfaw, A. Ayele, C. Ebinger, T. Furman, S. Harder, G.R. Keller, G.D. Mackenzie, P.K.H. Maguire, and G.W. Stuart Publisher: Geological Society of America Received: 14 Apr 2004 Revision Received: 27 Jul 2004 Accepted: 06 Aug 2004 First Online: 03 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2004) 32 (11): 949–952. https://doi.org/10.1130/G20737.1 Article history Received: 14 Apr 2004 Revision Received: 27 Jul 2004 Accepted: 06 Aug 2004 First Online: 03 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 K. Keranen, S.L. Klemperer, R. Gloaguen, EAGLE Working Group; Three-dimensional seismic imaging of a protoridge axis in the Main Ethiopian rift. Geology 2004;; 32 (11): 949–952. doi: https://doi.org/10.1130/G20737.1 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 Models of continental breakup remain uncertain because of a lack of knowledge of strain accommodation immediately before breakup. Our new three-dimensional seismic velocity model from the Main Ethiopian rift clearly images mid-crustal intrusions in this active, transitional rift setting, supporting breakup models based on dike intrusion and magma supply. The most striking features of our velocity model are anomalously fast, elongate bodies (velocity, Vp ∼6.5–6.8 km/s) extending along the rift axis, interpreted as cooled mafic intrusions. These 20-km-wide and 50-km-long bodies are separated and laterally offset from one another in a right-stepping en echelon pattern, approximately mimicking surface segmentation of Quaternary volcanic centers. Our crustal velocity model, combined with results from geologic studies, indicates that below a depth of ∼7 km extension is controlled by magmatic intrusion in a ductile middle to lower crust, whereas normal faulting and dike intrusion in a narrow zone in the center of the rift valley control extension in the brittle upper crust. This zone is inferred to be the protoridge axis for future seafloor spreading. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.