Authors: LAZZEZ MARZOUK, MOHAMED BEN YOUSSEF
Abstract: A transition facies between evaporate and clay, carbonate and siliciclastic deposits occurs within the Lower Cretaceous of Southern Tunisia. The sedimentary deposits comprise four major transgressive-regressive sedimentary sequences with distinctive sabkha, tidal to shallow carbonate marine platform, and mixed siliciclastic ramp environments. Sedimentation rates, as well as thickness and facies changes were controlled by tectonic, climatic and eustatic factors. Transgression pulses encompassing the whole Late Hauterivian-Barremian, Early Aptian and Late Albian have controlled the basin infill. Evaporate and siliciclastic systems pass gradually to carbonate deposition in the Chotts area. Our sedimentation model helps to decipher the roles of tectonics and, to a lesser extent, climate and palaeogeographic changes as the key factors of evaporate, carbonate and siliciclastic deposit sequences. Furthermore, sea level changes exert additional control on their environmental differentiations in such an ancient sedimentary basin. The sedimentary environments and palaeogegraphy in the Chotts chain during Hauterivian to Albian time are also reconstructed.
Keywords: Lower Cretaceous, depositional environment, palaeogeography, Chotts area, Tunisia
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