The onshore-offshore ENCENS project: Imaging the stretching of the continental lithosphere and inception of oceanic spreading in the eastern Gulf of Aden
Abstract
The eastern Gulf of Aden exemplifies several extensional processes that began 35 Ma ago from continental rifting to seafloor spreading at 2 cm/yr. Thin post-breakup sediment cover reveals the syn- and pre-rift basement fabric and the variable styles of conjugate margins along and across strike. A comprehensive multi- disciplinary study of the eastern part of the northern margin of the Gulf of Aden has been undertaken recently in the framework of the French margins program (GDR Marges) and the NERC with the long term objective to integrate in a consistent model of evolution, field observations where the margins crop out, results of marine geophysical survey where the margins are submerged and seismological observations of deep interior structure. A deep onshore-offshore seismic survey operated by IFREMER-GENAVIR was conducted between February, 3rd and March 14th 2006 off the Dhofar coast (southern Oman). We collect 67 multichannel seismic reflection profiles and 15 seismic refraction profiles acquired thanks to 60 stations. The shots have been recorded by 35 Ocean Bottom Seismometers (15 from IRD-Villefranche sur Mer and 20 from INSU Paris) and 25 seismological stations deployed onland in Southern Oman (18 stations from Encens-UK project funded by NERC and managed by RHUL ; 2 temporary and 4 permanent stations from Sultan Qaboos University ; 1 from ENS Paris). The network has been extended to the southern conjugate margin with 2 broadband stations deployed in Socotra island. The preliminary results show the evolution of the thickness of the crust from 35 km in the upper part of the margin to about 5 km in the ocean-continent transition. From our observations (low angle faults dipping toward the ocean or the continent imaged) we will propose rifting models responsible for the lithospheric stretching. The segmentation of the margins should be also precisely defined thanks to the multibeam bathymetry, the magnetism and the gravity acquired during the cruise.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.T53A1567L
- Keywords:
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- 7203 Body waves;
- 7205 Continental crust (1219);
- 7208 Mantle (1212;
- 1213;
- 8124);
- 8105 Continental margins: divergent (1212;
- 8124);
- 8109 Continental tectonics: extensional (0905)