Facies patterns within a Lower Jurassic upper slope to inner platform transect (Jbel Bou Dahar, Morocco)

Summary  This study concentrates on the description of a plat-from edge of a Lower Jurassic carbonate platform in the High Atlas of Morocco. The Jbel Bou Dahar displays a well-preserved platform to basin morphology with no major tectonic disturbance. A clear separation in facies belts could be made for the upper slope to platform interior environment. At the transition from the upper slope to the inner platform no prominent reef can be observed. Only a small zone exists withLithiotis mud-mounds and some corals, probably associated with sponges. It separates the ooid shoals of the platform interior from the upper-slope environment with its characteristic boulder beds. The angle of repose within the upper slope ranges from 23° to 35°, at the platform edge between 6° to 10° (Lithiotis mud-mounds zone), and within the platform interior from 1° to 4°. Nine microfacies types could be distinguished. These microfacies types include i.e. laminated pelmicrites, biopelsparites, and boundstones. Facies analysis showed that the sediments were deposited in facies belts 4 (slope of the platform) to 7 (open platform areas) afterWilson (1975).