Earliest magmatism in Ethiopia: Evidence for two mantle plumes in one flood basalt province

Research Article| October 01, 1998 Earliest magmatism in Ethiopia: Evidence for two mantle plumes in one flood basalt province Rhiannon George; Rhiannon George 1Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom Search for other works by this author on: GSW Google Scholar Nick Rogers; Nick Rogers 1Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom Search for other works by this author on: GSW Google Scholar Simon Kelley Simon Kelley 1Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom Search for other works by this author on: GSW Google Scholar Author and Article Information Rhiannon George 1Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom Nick Rogers 1Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom Simon Kelley 1Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1998) 26 (10): 923–926. https://doi.org/10.1130/0091-7613(1998)026<0923:EMIEEF>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 Rhiannon George, Nick Rogers, Simon Kelley; Earliest magmatism in Ethiopia: Evidence for two mantle plumes in one flood basalt province. Geology 1998;; 26 (10): 923–926. doi: https://doi.org/10.1130/0091-7613(1998)026<0923:EMIEEF>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 Tertiary magmatism in Ethiopia has been linked to the thermal influence of the Afar mantle plume. However, new laser 40Ar/39Ar ages for the volcanic succession in southern Ethiopia confirm the presence of two distinct magmatic phases at 45–35 Ma and 19–12 Ma. The earliest phase predates both extension and magmatism in northern Ethiopia by 15 m.y. and cannot be related to any simple model of melting in response to extension over a single mantle plume. We propose a model in which the Ethiopian province was initially related to the thermal influence of the Kenyan, and subsequently, the Afar mantle plume during northward movement of the African plate in the Tertiary. Support for this model comes from paleogeographic evidence that places southern Ethiopia ∼1000 km farther south than its current position during the early melting event at 45 Ma. Moreover, the rate of migration of the onset of magmatism from southern Ethiopia to Tanzania is similar to the rate of migration of the African plate over the same period. Comparable eruption rates in southern Ethiopia and Kenya further strengthen this link. In the light of this evidence, eruption rates ascribed to melting of the Afar mantle plume may be overestimated, which calls into question the potential for the Afar mantle plume to have had a significant effect on the biosphere. 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.