The offshore east African rift system: new insights from the Sakalaves seamounts (Davie Ridge,SW Indian Ocean) |
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| Authors: | Simon Courgeon Patrick Bachèlery Gwénael Jouet Stephan J Jorry Esther Bou Marcelle K BouDagher‐Fadel Sidonie Révillon Gilbert Camoin Emmanuelle Poli |
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| Institution: | 1. Department of Earth Sciences, University of Geneva, Geneva, Switzerland;2. Aix Marseille Univ, CNRS, IRD, Coll France, CEREGE, Aix‐en‐Provence, France;3. IFREMER, Unité Géosciences Marines, Plouzané, France;4. Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, Clermont‐Ferrand, France;5. Earth Science, University College London, London, UK;6. SEDISOR/UMR 6538, Laboratoire Géosciences Océans, IUEM, Plouzané, France;7. TOTAL Exploration and Production, CSTJF, Pau, France |
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| Abstract: | The offshore branch of the East African Rift System (EARS) has developed during Late Cenozoic time along the eastern Africa continental margin. While Neogene–Pleistocene extensional tectonic deformation has been evidenced along the northern segment of the Davie Ridge, the spatial extent of deformation further south remains poorly documented. Based on recent and various oceanographic datasets (bathymetric surveys, dredge samples and seismic profiles), our study highlights active normal faulting, modern east–west extensional tectonic deformation and Late Cenozoic alkaline volcanism at the Sakalaves Seamounts (18°S, Davie Ridge) that seem tightly linked to the offshore EARS development. In parallel, rift‐related tectonic subsidence appears responsible for the drowning of the Sakalaves Miocene shallow‐water carbonate platform. Our findings bring new insights regarding the development of the EARS offshore branch and support recent kinematic models proposing the existence of a plate boundary across the Mozambique Channel. |
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