Implications of salt–sediment interactions on the architecture of the Gulf of Lions deep-water sedimentary systems—western Mediterranean Sea * Antonio Tadeu dos Reis a, * , Christian Gorini b , Alain Mauffret c a Departamento de Oceanografia/UERJ-Brazil, Rua Sa ˜o Francisco Xavier, 524, 48 Andar, Maracana ˜, Rio de Janeiro, RJ, CEP 22550-900, Brazil b Laboratoire des Processus et Bilans des Domaines Se ´dimentaires, Universite ´ des Sciences et Technologies de Lille1/UNST, Ba ˆ timent SN5, 59655 Villeneuve d’Ascq, France c Laboratoire de Tectonique, Universite ´ Pierre & Marie Curie/UPMC, France, 4, Place Jussieu, Tour 26-0, Case 129, 75252 Paris Cedex, France Received 4 January 2003; accepted 7 March 2005 Abstract We integrated structural analysis of multichannel seismic data and isopach maps of the Quaternary sedimentary cover to evaluate how salt tectonics has influenced the stratigraphic evolution offshore the Gulf of Lions. The interplay between salt tectonics and sedimentation occurs at two scales. At local scale, listric normal faults create bathymetric relief able to deviate sediment transport axes, with implications on depocenters configuration. At depocenter scale, overburden vertical movements due to salt evacuation or salt diapiric rise create sub-basins, providing accommodation space for clastic deposition. These mechanisms have significant implications on the architecture and the internal organization of turbidite systems offshore the Gulf of Lions. q 2005 Elsevier Ltd. All rights reserved. Keywords: Salt tectonics; Basin analysis; Gulf of Lions 1. Introduction The stratigraphic evolution of the Gulf of Lions has been increasingly studied during the last decades. However, relatively few studies have dealt with the sedimentary evolution of deep-water Plio-Quaternary sedimentary complexes (e.g. Got et al., 1979; Droz, 1983, 1991; Droz and Bellaiche, 1985; Bellaiche et al., 1988, 1989; Bellaiche and Mart, 1995). The depositional models proposed in these studies are largely based on seismic stratigraphy emphasizing the role of sedimentological parameters related to glacio-eustatic fluctuations as the major factors control- ling the stratigraphic architecture of deep depositional environments. Such models are essentially based on the growth pattern of lens-shaped sedimentary units of the Rho ˆne deep-sea fan and the ridge-like depositional units of the Marseille and Grand-Rho ˆne ridges (Droz, 1983, 1991; Droz and Bellaiche, 1985; Bellaiche and Mart, 1995). Special attention has also been paid to sediment transfer processes, notably through the extensive network of sub- marine canyons, and to the efficiency of mass-wasting processes that feed the corresponding deep-water deposits (Got et al., 1979; Droz, 1983, 1991; Coutellier, 1985; Bellaiche and Mart, 1995; Fouchet, 1998; Berne ´ et al., 1999; dos Reis, 2001; Baztan, 2004). Although the occurrence of salt tectonics has long been recognized in the study area (e.g. Leenhardt, 1967, 1968; Droz, 1983; Gorini et al., 1993), relatively little has been published about the evolution of the related salt system. Le Cann (1987) was the first author to propose a study aiming specifically at the salt tectonic framework, focusing on the region affected by salt diapirism. A systematic structural mapping was conducted in the deep Provenc ¸al basin, where two trends of salt walls, trending SW–NE and NW–SE, were recognized. Previous analyses of syn–rift structures of the basin were incorporated to explain both the salt diapirs geometry and lineations. Le Cann (1987) hypothesized that the NE–SW continental–oceanic crust boundary and the Oligocene NW–SE syn–rift structures were the features controlling, respectively, the SW–NE and NW–SE diapirs trends in the deep basin. Because the ocean–continent Marine and Petroleum Geology 22 (2005) 713–746 www.elsevier.com/locate/marpetgeo 0264-8172/$ - see front matter q 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpetgeo.2005.03.006 * This is contribution no. 2047 of GDR Marges, Gulf of Lions. * Corresponding author. Fax: C55 21 2587 7692. E-mail address: treis@uerj.br (A.T. dos Reis).