Geophysical evidence for a transform margin offshore Western Algeria: a witness of a subduction-transform edge propagator?

Type Article
Date 2015-02
Language English
Author(s) Badji Rabia1, 2, 3, Charvis Philippe2, Bracene Rabah1, Galve Audrey2, Badsi Madjid1, Ribodetti Alessandra2, Benaissa Zahia3, Klingelhoefer FraukeORCID4, Medaouri Mourad1, Beslier Marie-Odile2
Affiliation(s) 1 : Sonatrach, Division exploration, Bât C, Avenue du 1er Novembre, B.P 68M, Boumerdes, Algeria.
2 : Université Nice Sophia Antipolis, IRD, CNRS, Observatoire de la Côte d'Azur, Géoazur, 250 rue Albert Einstein, F-06560, Sophia Antipolis, France
3 : Université des sciences et de la technologie Houari Boumediene, USTHB, FSTGAT, el-alia Algiers, Algeria
4 : Ifremer, Department of marine Geosciences, ZI de la Pointe de Diable, CS10070, Plouzané, France
Source Geophysical Journal International (0956-540X) (Wiley / Blackwell), 2015-02 , Vol. 200 , N. 2 , P. 1027-1043
DOI 10.1093/gji/ggu454
WOS© Times Cited 12
Keyword(s) Seismic tomography, Continental margins: transform, Crustal structure, Africa, Europe.
Abstract For the first time, a deep seismic data set acquired in the frame of the Algerian-French SPIRAL program provides new insights regarding the origin of the westernmost Algerian margin and basin. We performed a tomographic inversion of traveltimes along a 100-km-long wide-angle seismic profile shot over 40 ocean bottom seismometers offshore Mostaganem (Northwestern Algeria). The resulting velocity model and multichannel seismic reflection profiles show a thin (3-4 km thick) oceanic crust. The narrow ocean-continent transition (less than 10 km wide) is bounded by vertical faults and surmounted by a narrow almost continuous basin filled with Miocene to Quaternary sediments. This fault system, as well as the faults organized in a negative-flower structure on the continent side, marks a major strike-slip fault system. The extremely sharp variation of the Moho depth (up to 45 +/- 3 degrees) beneath the continental border underscores the absence of continental extension in this area. All these features support the hypothesis that this part of the margin from Oran to Tenes, trending N65-N70 degrees E, is a fossil subduction-transform edge propagator fault, vestige of the propagation of the edge of the Gibraltar subduction zone during the westward migration of the Alboran domain.
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Badji Rabia, Charvis Philippe, Bracene Rabah, Galve Audrey, Badsi Madjid, Ribodetti Alessandra, Benaissa Zahia, Klingelhoefer Frauke, Medaouri Mourad, Beslier Marie-Odile (2015). Geophysical evidence for a transform margin offshore Western Algeria: a witness of a subduction-transform edge propagator? Geophysical Journal International, 200(2), 1027-1043. Publisher's official version : https://doi.org/10.1093/gji/ggu454 , Open Access version : https://archimer.ifremer.fr/doc/00255/36670/