Early continental breakup boundary and migration of the Afar triple junction, Ethiopia

Research Article| September 01, 2003 Early continental breakup boundary and migration of the Afar triple junction, Ethiopia Samson Tesfaye; Samson Tesfaye 1Department of Earth and Atmospheric Sciences, St. Louis University, St. Louis, Missouri 63103, USA Search for other works by this author on: GSW Google Scholar David J. Harding; David J. Harding 2NASA (National Aeronautics and Space Administration), Goddard Space Flight Center, Geodynamics Branch, Greenbelt, Maryland 20771, USA Search for other works by this author on: GSW Google Scholar Timothy M. Kusky Timothy M. Kusky 3Department of Earth and Atmospheric Sciences, St. Louis University, St. Louis, Missouri 63103, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Samson Tesfaye 1Department of Earth and Atmospheric Sciences, St. Louis University, St. Louis, Missouri 63103, USA David J. Harding 2NASA (National Aeronautics and Space Administration), Goddard Space Flight Center, Geodynamics Branch, Greenbelt, Maryland 20771, USA Timothy M. Kusky 3Department of Earth and Atmospheric Sciences, St. Louis University, St. Louis, Missouri 63103, USA Publisher: Geological Society of America Received: 12 Mar 2002 Revision Received: 23 Oct 2002 Accepted: 09 Dec 2002 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2003) 115 (9): 1053–1067. https://doi.org/10.1130/B25149.1 Article history Received: 12 Mar 2002 Revision Received: 23 Oct 2002 Accepted: 09 Dec 2002 First Online: 02 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 Samson Tesfaye, David J. Harding, Timothy M. Kusky; Early continental breakup boundary and migration of the Afar triple junction, Ethiopia. GSA Bulletin 2003;; 115 (9): 1053–1067. doi: https://doi.org/10.1130/B25149.1 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 SocietyGSA Bulletin Search Advanced Search Abstract Megascale accommodation zones mark the early continental breakup boundary of the Afro-Arabian plateau in Ethiopia. Motion along these megascale accommodation zones enabled the different arms of the Afar RRR (rift-rift-rift) triple junction to join together. An arcuate accommodation zone ∼45 km wide and ∼60 km long marks the transition from the N25°W-striking Southern Red Sea Rift trend in the western Afar margin to the N25°E-striking Main Ethiopian Rift. Another accommodation zone ∼80 km long marks the transition between the northeast- to north-northeast–trending Main Ethiopian Rift and the nearly east-trending Gulf of Aden. The positions of accommodation zones where rift orientations change by ∼50° suggest that they served as soft linking points between the kinematically "misaligned" arms of the triple junction during the initial breakup of the Afro-Arabian dome.We use structural features to infer the present location of the triple junction in the Lake Abhe area. On the basis of the location of the paleo–triple junction, deduced from the position of accommodation zones and geomorphic considerations, it is estimated that the Afar triple junction has migrated ∼1.5° (∼160 km) in a north- northeast direction with respect to the African (Nubian) plate. The estimated amount of migration of the Afar triple junction is less than the 200 km migration expected from plate-kinematic analysis. This discrepancy suggests either a slower rate of spreading than the current ∼1.6 cm/yr (Africa-Arabia) during the early phase of rifting or a later early Miocene rather than Oligocene–Miocene age for the initiation of tectonic activity in the triple junction. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.