Multiphase inversions and their impact on petroleum systems of the Western Mediterranean basins and margins (with focus on North Algeria and France)

Abstract

The architecture of the European and African margins of the Western Mediterranean basin has been strongly impacted by successive geodynamic episodes, including (1) the collapse of the Hercynian orogen and negative inversion of former Carboniferous thrusts during the Permian, (2) the Triassic to Liassic rifting of the Tethys and the subsequent thermal subsidence of its passive margins from the Dogger until the Upper Cretaceous, (3) early Alpine inversions from the Upper Cretaceous until the Eocene in the foreland of the Alps and the Pyrenees in the north, and in the Saharan Atlas in North Africa, (4) renewed extension, negative inversion of former Eocene thrusts, resulting in the back-arc rifting of the gulfs of Lion and Valencia and the opening of the Algerian basin during the Oligocene and early Miocene, and (5) renewed onshore inversion episodes in the foothills of the Alps and Tellian thrust belts during the Plio-Quaternary, coeval with the development of incipient subduction in the deep offshore basins at the toe of the North Algerian, Sicilian and Ligurian margins.

In such complex tectonic context, Permian, Jurassic, Cretaceous, Oligocene and Neogene source rocks display very contrasted burial histories. They still account for effective petroleum systems, despite the fact that only minor oil and gas accumulations have yet been discovered in Southern France and North Algeria. The main exploration risks are actually related to the destruction of early traps and large amounts of erosion induced by tectonic uplift during early inversion episodes, to the limited and recent burial of the Messinian source rocks in the Mediterranean offshore, and to the current lack of exploration wells in the subsalt series of the Western Mediterranean as a whole.

AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015