SYNSEDIMENTARY TECTONICS IN CENTRAL TUNIS IA (JEBEL-MRHILA AREA) DURING THE APTIAN-ALBIAN

The important sedimentary gaps the variations of thicknesses and facie s which characterize the Aptian-Albian series in the J. Mrhila area, a re linked, at least partly, to the action of two tectonic features. 1. The Mrhila-Cherichira fault, with a NNE-SSW direction, is responsible for the collapse of the area located north of this major accident; th e southwards tilt of this area made the accumulation of very thick mar ine sediments possible, during Clansayesian to Late Albian time, at Ko udiat El Beida (KEB) and in Bled El Gouna 1 (BEG.1) wells. These sedim ents do not occur in the uplifted area, south of the fault. 2. The sec ond feature, corresponding to the Sbiba fault, with a N 140 direction, had as effect, the reduction of the Albian series within the Tiouacha 1 (Ti.1) boring. This variation is significant, even if it is, by far , less important than that occurring on both sides of the major NNE-SS W fault. It seems that this Sbiba fault played a role in Clansaysian t o Upper-Albian sedimentation, which resulted in the formation of a los angic basin. (C) Academie des sciences/Elsevier, Paris.