HR: 1340h
AN: T23B-1409    [Abstracts]
TI: Ocean deformation processes at the Caribbean-North America-South America triple junction: Initial results of the 2007 ANTIPLAC marine survey
AU: Benard, F
AF: IFP, 1-4, av. Bois-Preau, Rueil-Malmaison, 92852, France
AU: * Deville, E
AF: IFP, 1-4, av. Bois-Preau, Rueil-Malmaison, 92852, France
AU: Le Drezen, E
AF: IFREMER, DRO-GM, BP 70, Plouzané, 29280, France
AU: Loubrieu, B
AF: IFREMER, DRO-GM, BP 70, Plouzané, 29280, France
AU: Maltese, L
AF: IFREMER, DRO-GM, BP 70, Plouzané, 29280, France
AU: Patriat, M
AF: IFREMER, DRO-GM, BP 70, Plouzané, 29280, France
AU: Roest, W
AF: IFREMER, DRO-GM, BP 70, Plouzané, 29280, France
AU: Thereau, E
AF: IFREMER, DRO-GM, BP 70, Plouzané, 29280, France
AU: Umber, M
AF: IFREMER, DRO-GM, BP 70, Plouzané, 29280, France
AU: Vially, R
AF: IFP, 1-4, av. Bois-Preau, Rueil-Malmaison, 92852, France
AB: Marine geophysical data (multibeam and seismic lines) acquired in 2007 (ANTIPLAC survey) in the North-South Americas-Caribbean triple point (Central Atlantic, Barracuda and Tiburon ridges area), provide information about the structure, the tectonic processes and the timing of the deformation in this large diffuse zone of polyphase deformation. The deformation of the plate boundary between the north and south Americas is distributed on several structures located in the Atlantic plain, at the front of the Barbados accretionary prism. In this area of deformation of the Atlantic oceanic lithosphere, the main depressions and transform troughs are filled by Late Pliocene-Pleistocene turbidite sediments, especially in the Barracuda trough, north of Barracuda ridge. These sediments are not issued from the Lesser Antilles volcanic arc but they are sourced from the East, probably by the Orinoco turbidite distal system, through channels transiting in the Atlantic abyssal plain. These Late Pliocene- Quaternary sediments show locally spectacular evidences of syntectonic deformation. It can be shown notably that Barracuda ridge includes a pre-existing transform fault system which has been folded and uplifted very recently during Pleistocene times. This recent deformation has generate relieves up to 2 km high with associated erosion processes notably along the northern flank the Barracuda ridge. The subduction of these recently deformed ridges induces deformation of earlier structures within the Barbados accretionary prism. These asperities within the Atlantic oceanic lithosphere which is subducted in the Lesser Antilles active margin are correlated with the zone of intense seismic activity below the volcanic arc.
DE: 0930 Oceanic structures
DE: 0935 Seismic methods (3025, 7294)
DE: 3039 Oceanic transform and fracture zone processes
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 3045 Seafloor morphology, geology, and geophysics
SC: Tectonophysics [T]
MN: 2007 Fall Meeting