Lithofacies and biostratigraphical correlation of marine Carboniferous rocks in the Tindouf Basin, NW Africa

Abstract

Spatial and temporal variations of Carboniferous sediment accumulation within the northwestern part of the northern flank of the Tindouf Syncline in Saharan Morocco allowed to distinguish 16 lithofacies types. The predominant sedimentation pattern is cyclic, with the overall succession recording a major regressive trend. Outer platform siliciclastics in the lower part (Tournaisian and Visean) pass up to middle and inner platform mixed siliciclastic and carbonate sediments (late Visean–Serpukhovian) and finally to continental sandstones in the Bashkirian capping the marine carbonate sedimentation. The lack of similarities in a correlation with southern outcrops in the Tindouf Syncline suggests tectonically controlled sedimentation. The upper Tournaisian to lower Bashkirian succession records the incipient uplift of the Anti-Atlas Mountains, changing the paleogeography and, therefore, affecting the paleoecologic conditions, as well as the sedimentary environments in the Tindouf Basin. It is suggested that from the Serpukhovian onwards, much of the Anti-Atlas was uplifted, leading to subaerial conditions, while during the late Visean, only a few small inliers had emerged. Although the number of Proterozoic emergent inliers of the Anti-Atlas is unknown, during the late Visean, the Anti-Atlas Mountain belt is regarded as an emerging structure, with a distinct influence on the paleobiogeography of the region.