Cenomanian-Turonian Organic Facies Onshore and Offshore, Israel: Prognosis for Petroleum Exploration

S. Lipson-Benitah, A. Flexer, B. Derin, A. Rosenfeld, A. Honigstein

The Cenomanian-Turonian marine sediments of Israel are rich in organic matter: black shales and bituminous marls. They accumulated in a north-south oriented chain of basins located along the paleoshoreline separating the broad platform in the east and the open sea in the west.

A detailed biostratigraphy based on planktonic foraminifers, ostracods, and organic composition and content is presented. The range of these organic levels is centered across the Cenomanian-Turonian boundary (Whiteinella archeocretacea zone) extending to early-middle Turonian (Helvetoglobtruncana helvetica zone). These new data contribute to the central Tethys record and corroborate the wide distribution of organic-rich sedimentation induced by marine anoxia.

The paleo-oceanography and economic implications of this anoxic event are discussed. Upwelling and an expanded oxygen-depleted zone coupled with regional tectonovolcanism controlled production and preservation of organic matter. Primary production was stimulated by enhanced upwelling and nutrients derived from the Carmel volcanism. As the platform was progressively flooded, the anoxic column moved from slope to shelf basins, reaching the structural high of the Carmel only by the middle Turonian.

These organic-rich beds associated with eustatic rise could be potential source rocks if thermally matured. Such sediments might occur in the offshore Pleshet basin, where middle Cretaceous organic deposits are covered by 4 to 5 km-thick sediments. Appropriate structures and sealing (evaporites, shales) provide the required conditions for entrapment and conservation of the in-situ generated hydrocarbon, minimizing loss by migration.

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