Intact seismic-scale platforms and ramps in the Lower to Middle Jurassic of Morocco: implications for stratal anatomy and lithofacies partitioning.
Résumé
The Jurassic carbonate platforms of the central High Atlas in Morocco are well known for several high-quality outcrops. In the central High Atlas, there are two complementary locations that offer critical lessons for our understanding of Jurassic carbonate system evolution in extensional basins: a Lower Jurassic high-relief, carbonate platform with steep slopes that developed on the footwall of a rotating fault block in an active half-graben (Djebel Bou Dahar [DBD]) and an upper Lower to Middle Jurassic low-angle prograding carbonate ramp rich in ooids (Amellago ramp [AR]). The DBD and AR outcrops provide superbly exposed, structurally intact, and fully accessible platform to basin transects. They provide valuable analogs for depositional geometries at reservoir and seismic scales that are highly relevant for hydrocarbon exploration and production. The DBD serves as an analog for isolated carbonate platforms developed in rift basins (particularly synrift carbonate platforms with a coral calcareous sponge and microbial boundstone facies belt in the upper slope and margin). The AR provides one of the rare examples whereby a large-scale oolitic ramp can be examined in great detail, providing an analog for a range of oolitic reservoirs, mostly Mesozoic.