Geological evolution and structural style of the Palaeozoic Tafilalt sub-basin, eastern Anti-Atlas (Morocco, North Africa) E. A. TOTO 1 , F. KAABOUBEN 1 , L. ZOUHRI 2 * , M. BELARBI 3 , M. BENAMMI 1 , M. HAFID 3 and L. BOUTIB 1 1 Equipe de Ge ´ ophysique et Ge ´ othechnique, De ´ partement de Ge ´ ologie, Faculte ´ des Sciences, Universite ´ Ibn Tofail, Ke ´ nitra, Morocco 2 UMR CNRS 8110, Processus et Bilans des Domaines Se ´ dimentaires, UFR des Sciences de la Terre, Universite ´ de Lille I, 59655 Villeneuve d’Ascq, France 3 Office National des Hydrocarbures et des Mines, Rabat, Morocco The Tafilalt is one of a number of generally unexplored sub-basins in the eastern Anti-Atlas of Morocco, all of which probably underwent a similar tectono-stratigraphic evolution during the Palaeozoic Era. Analysis of over 1000 km of 2-D seismic reflection profiles, with the interpretation of ten regional seismic sections and five isopach and isobath maps, suggests a multi-phase deformation history for the Palaeozoic-aged Tafilalt sub-basins. Extensional phases were probably initiated in the Cambrian, followed by uniform thermal subsidence up to at least the end of the Silurian. Major extension and subsidence did not begin prior to Middle/Upper Devonian times. Extensional movements on the major faults bounding the basin to the north and to the south took place in synchronisation with Upper Devonian sedimentation, which provides the thickest part of the sedimentary sequence in the basin. The onset of the compressional phase in Carboniferous times is indicated by reflectors in the Carboniferous sequence progressively onlapping onto the Upper Devonian sequence. This period of compression developed folds and faults in the Upper Palaeozoic-aged strata, producing a structural style characteristic of thin-skinned fold and thrust belts. The Late Palaeozoic units are detached over a regional de ´collement with a northward tectonic vergence. The folds have been formed by the process of fault-propagation folding related to the thrust imbricates that ramp up-section from the de ´collement. Copyright # 2007 John Wiley & Sons, Ltd. Received 22 November 2006; revised version received 17 September 2007; accepted 18 September 2007 KEY WORDS Palaeozoic sub-basin; structural style; seismic sections; Tafilalt; Anti-Atlas; Morocco 1. INTRODUCTION A set of small Palaeozoic basins lies in the eastern part of the Anti-Atlas (Morocco). They are obvious on geologic maps of southern Morocco (Figure 1). Despite their relatively limited surface outcrop, these basins provide significant evidence to interpret and constrain the Palaeozoic history of the northwest African craton. The principal palaeogeographic characteristics and the tectonic evolution of northwest Africa have been described in numerous papers (Guiraud et al. 1987, 2000, 2001; Guiraud and Maurin 1991; Guiraud and Bosworth 1999; Guiraud 2001; Pique ´ et al. 2002; Houari and Hoepffner 2003; Hoepffner et al. 2005). Synsedimentary faults in the sub-basins exhibit both extensional and reverse movements indicating evidence for superimposed tectono-sedimentary phases. Palaeozoic oil-producing basins found in western Algeria, south of the High Atlas (Guiraud et al. 2005), in the GEOLOGICAL JOURNAL Geol. J. 43: 59–73 (2008) Published online 8 November 2007 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/gj.1098 * Correspondence to: L. Zouhri, UMR CNRS 8110, Processus et Bilans des Domaines Se ´dimentaires, UFR des Sciences de la Terre, Universite ´ de Lille I, 59655 Villeneuve d’Ascq, France. E-mail: Lahcen.zouhri@gmail.com Copyright # 2007 John Wiley & Sons, Ltd.