Sedimentological Study of Sandy and Shaly Deposits (Beglia Formation) in Cap Bon Area

M. N. Mahjoub, M. Khessibi

A sedimentological study of sandy and shaly deposits of the Beglia formation has been made in Cap Bon (northeast of Tunisia) to define a sedimentological and paleogeographical model which could be extrapolated into the Gulf of Hammamet. The main results follow. (1) The Beglia formation is Serravalian in age and has a migratory deltaic complex facies which includes river and marine affinities (flood plain and tidal). Ten megasequences have been recognized. (2) Three intervals within the Beglia have been studied in detail: the intra-Mahmoud sandstone member, the grain flow and debris flow with granitic pebbles of the fourth megasequence, and the shelly limestone level of the sixth megasequence. These indicate a northwest-southeast depositional trend which we consider the main direction of the middle Miocene detrital deposits in northeastern Tunisia. (3) The fine and well-sorted sandstones which extend up to hectometric and kilometric size, observed in outcrop, are the distal zones of the migr tory fans and bars. (4) These sandstones bodies, because of their relative small size within our deltaic model, do not extend to the Gulf of Hammamet. The sandstones offshore have produced hydrocarbons in several areas. They are the distal equivalent of the poorly sorted and coarse channel deposits studied in the outcrops.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.