Abstract New U–Pb zircon ages from the Eastern Saghro massif in the Anti-Atlas of Morocco demonstrate a link between Pan-African transpressive collision at c. 600 Ma and transtension caused by the onset of Cadomian subduction and arc development from c. 570 Ma onwards. We present new U–Pb laser ablation inductively coupled plasma mass spectrometry ages of detrital and magmatic zircon from the Saghro, M'Gouna, and Ouarzazate Groups. The siliciclastic deposits of the Saghro Group were deposited in a back-arc setting developed on stretched continental crust of the West African margin. Collision with the Atlas–Meseta domain led to the closure of the back-arc basin before 600 Ma. Time of exhumation and surface exposure of the newly formed Pan-African basement is bracketed to c. 30 Ma owing to the maximum depositional age of 571 ± 4 Ma of the overlying M'Gouna Group. The U–Pb age of 567 ± 4 Ma for the lowermost ignimbrite of the Ouarzazate Group limits the time for the deposition of the M'Gouna Group to less than 4 Ma. The Pan-African orogeny was finished at c. 600 Ma whereas the onset of transtension related to Cadomian back-arc formation was very much younger from c. 570 Ma onwards.

Abstract The lower continental slope of Morocco’s west coast has three varying morphologies of buried deep-water sediment waves. Detailed mapping of a 1,064 km 2 seismic survey acquired in the Safi Haute Mer seismic block reveals numerous Jurassic-and Cretaceous-age features that range from small, <12 m thick amplitude anomalies to 130 m high migrating waves. Early proto-Atlantic deposition in Safi Haute Mer initiated in the Triassic with syn-rift accumulation in basement half-grabens basinward of the modern Moroccan salt front. Sedimentation continued through the Mesozoic with the deposition of turbidites, progradation of clinoforms, and culminating in multiple Late Cretaceous regionally expansive mass-transport complexes (>20,000 km 2 ). Tertiary stratigraphy consists of multiple thin, pelagic drapes and unconformities. The complex history of sedimentation and tectonics gave rise to three styles of sediment waves found within the study area. These three types are the (1) type J1, small poorly imaged, Jurassic age, locally generated wave forms that have crestal lengths of up to 12 km and wave lengths less than 1 km with little or no vertical expression; (2) type K1 are Early Aptian constructional sediment waves (~130 m thick) built by contour currents that moved along-slope adjacent to sea-floor highs produced by shallow buried salt; and (3) type K2, Late Albian and Early Cenomanian sediment waves built by along-slope currents on a relatively stable slope showing updip migration. The type K2 sediment wave field exhibits wave heights of 40 m and wavelengths of 1 km, and is continuous over the entire study area.

Abstract Recent publications ( Hudec, 2006 ; Hudec et al. , 2008) have renewed discussion of mini-basin formation processes and resultant deposits in basins overlying mobile substrate margins (including salt, shale, and crustal subsidence) around the world. Mini-basin provinces produce enormous volumes of hydrocarbons, besides forming supramobile substrate topography that controls how sediment volumes are transferred from shelf edges to ultimate sinks in the deep ocean. Increasing exploration and production in ever-deepening regions of the world’s oceans warrant a revisit to many of these concepts of accommodation development, sediment generation, sediment movement, and ultimate geometry and distribution of resulting deposits. The objective of this study is to utilize an extensive 3D seismic data volume from the Safi Haute Mer (SHM) permit area, offshore Morocco to examine the Cretaceous through Tertiary fill of an isolated minibasin and to investigate the effect of paleogeomorphologic bathymetry as an indication of tectonic state within the margin. Our hypothesis is that mini-basins change their fill architecture and composition in response to changes in slope, bathymetry, bottom topography, sediment sources, and structural stability. Therefore, in basins undergoing deformation, such as along tectonically active margins, under conditions of rafting or in shelf-distal locations, systematic changes in these variables should be reflected in geometry and morphology of the fill making up basin strata. Seismic attribute analysis is used to investigate the change in character of the fill through time, and the influence of regional structural features developed during the evolution of the Moroccan continental slope is combined with our observations to develop a model for the minibasin’s evolution. A methodology is proposed to reconstruct the tectonic evolution of the mini-basin by implementing observations from geomorphological and structural analysis using 3D seismic data. Results from this distal slope mini-basin show that the evolutionary history can be described in four phases of structural development, the latter three of which are linked to four distinct phases of sedimentary fill. Observations noted from each stage of the analytical process are compared and contrasted to existing models of mini-basin development to evaluate their validity and application in a distal, sediment-starved setting such as the lower slope of the Morocco continental margin.