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

This study concentrates on the description of a platform edge of a Lower Ju rassic carbonate platform in the High Atlas of Morocco. The Jbel Bou Dahar displays a well-preserved platform to basin morphology with no major tecton ic disturbance. A clear separation in facies belts could be made for the upper slope to pla tform interior environment. At the transition from the upper slope to the i nner platform no prominent reef can be observed. Only a small zone exists w ith Lithiotis 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 with in the upper slope ranges from 23 degrees to 35 degrees, at the platform ed ge between 6 degrees to 10 degrees (Lithiotis mud-mounds zone), and within the platform interior from 1 degrees to 4 degrees. Nine microfacies types c ould be distinguished. These microfacies types include i.e. laminated pelmi crites, biopelsparites, and boundstones. Facies analysis showed that the se diments were deposited in facies belts 4 (slope of the platform) to 7 (open platform areas) after WILSON (1975).