TECTONIC-SEDIMENTARY PHENOMENA ORIGINALIT Y AT THE TERMINAL YPRESIAN IN CENTRAL-NORTHERN TUNISIA (KAIROUAN AREA)

In central-northern Tunisia, the Ypresian deposits make up a carbonate megasequence which is surrounded by Palaeocene clays at the base and by the Lutetian-Priabonian marls at the top.The structural analysis of the Ypresian limestones in different scales, shows that this period i s characterized by synsedimentary movements (extensional strike-slip f aults). These movements have produced multiscales fracturing in blocks with the terminal sedimentation. This deformation is accompanied by t he appearance of original synsedimentary and syndiagenetic phenomena. They occur in several stages along submarine fault scarps generating b reccias and rotational landslides acting upon soft sediments (hydropla stic structures), at a period when one notes rapide variation in the d irections of extension (49-50 Ma ago).