The offshore east african rift system: new insights from the sakalaves seamounts (Davie Ridge, SW Indian Ocean)

Type Article
Date 2018-10
Language English
Author(s) Courgeon Simon1, 2, 3, Bachelery Patrick4, Jouet Gwenael3, Jorry StephanORCID3, Bou Esther4, Boudagher-Fadel Marcelle K.5, Revillon Sidonie6, Camoin Gilbert2, Poli Emmanuelle7
Affiliation(s) 1 : Univ Geneva, Dept Earth Sci, Rue Maraichers 13, CH-1205 Geneva, Switzerland.
2 : Aix Marseille Univ, CNRS, Coll France, IRD,CEREGE, Aix En Provence, France.
3 : IFREMER, Unite Geosci Marines, Plouzane, France.
4 : Univ Clermont Auvergne, CNRS, Lab Magmas & Volcans, IRD,OPGC, Clermont- Ferrand, France.
5 : UCL, Earth Sci, London, England.
6 : IUEM, SEDISOR UMR 6538, Lab Geosci Oceans, Plouzane, France.
7 : CSTJF, TOTAL Explorat & Prod, Pau, France.
Source Terra Nova (0954-4879) (Wiley), 2018-10 , Vol. 30 , N. 5 , P. 380-388
DOI 10.1111/ter.12353
WOS© Times Cited 5
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 data sets (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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Courgeon Simon, Bachelery Patrick, Jouet Gwenael, Jorry Stephan, Bou Esther, Boudagher-Fadel Marcelle K., Revillon Sidonie, Camoin Gilbert, Poli Emmanuelle (2018). The offshore east african rift system: new insights from the sakalaves seamounts (Davie Ridge, SW Indian Ocean). Terra Nova, 30(5), 380-388. Publisher's official version : https://doi.org/10.1111/ter.12353 , Open Access version : https://archimer.ifremer.fr/doc/00452/56344/