Climatic and tectonic control of Ordovician sedimentation in the western and central High Atlas (Morocco)

The sedimentology of Ordovician deposits in the western and central High Atlas mountains defines several depositional environments: tidal-dominated littoral; wave- and storm-dominated delta, tidal-dominated delta; wave- and storm-dominated shelf. The sediments are mainly siliciclastic and mixed limestone-sili ciclastic, with sparse deposits of ooidal ironstone, basal transgressive sand, and glauconite. The sediments were derived from different levels of the Pan-African chain in the Lower and Middle Ordovician, and from the Sahara in the Upper Ordovician. The sedimentary and sequential evolution indicate that deposition occurred in two independents epeiric seas, influenced mainly by the interplay of tectonics and climate. 2004 Elsevier Ltd. All rights reserved.