Lower to Middle Miocene Deposits of North-East Tunisia: Implied Facies Evolution and Tectonic-Sedimentary Control

Abstract

This work was the result of a scientific collaboration between the faculty of sciences of Tunis (FST) Tunis –El Manar University (which provides the logistic support) and the Lundin Petroleum Tunisia (which provides wells and seismic data). It aims to study the response of the Miocene sedimentary systems, in the North-East of Tunisia, to the global events occurring during sedimentation. Miocene deposits organization is complex and evolved in time and space. It is characterized by pedogenetic alteration, great sedimentary supply with frequently, bad preservation and stratigraphic lacuna. In this context, a multidisciplinary approach integrating biostratigraphy, facies analysis, interpretation of depositional environments and seismic correlations has been adopted. It has allowed us to mark the distribution and the thickness of the facies (petroleum objects) and to understand the general evolution of sedimentary systems related to tectonic, eustatic and climatic events that they have been recorded. The compilation of the data shows that several modifications of the depositional environments, during the Burdigalian-Langhian period, have occurred in the studied area. Two transgressive events are recognized and major discontinuities have been highlighted. The sudden changes of thickness and the individualization of the Miocene microbasins are arguable in favor of a tectonic control.