CRETACEOUS SYNSEDIMENTARY TECTONICS IN THE ATLAS SYSTEM OF CENTRAL MOROCCO

Cretaceous sediments in Central Morocco were deposited in various depo sitional environments and comprise an undetermined Lower Cretaceous ba se up to Maastrichtian. The sedimentary columns show a similar facies evolution. Basal unconformities, conglomeratic layers and significant differences in thicknesses reflect pre- and synsedimentary vertical te ctonic movements. These tectonic movements took place along large NE/S W striking fault systems, one of the major features of the present tec tonic framework. Permanent displacement of the subsidince maxima in ti me and space indicate the development of small tectonic blocks which w ere tilted and/or compressed between the fault zones. High sedimentati on rates in areas of strong subsidence, however, prevented the evoluti on of intraplatformbasins. Although tectonic influence was important, eustatic sea level changes ruled the whole sedimentary regime.