Abstract: Tectonics Versus Eustasy: North African Mesozoic And Cenozoic Facies Patterns And Hydrocarbon Exploration

Manfred Karl Hauptmann

NNE-SSW Atlantic trending, ENE-WSW to E-W Mediterranean trending, as well as NW-SE trending fault systems of Variscan or even pre-Variscan age controlled the facies distribution between the Atlantic shoreline of Morocco in the west and the eastern margin of the Pelagian block east of the Maltese Islands. This region incorporates large parts of Algeria and Tunisia.

Multiple reactivation of these fault zones as normal faults and as reverse faults with significant strike-slip components occurred during a period beginning with Triassic red bed sedimentation until Recent times. Fault movements reflect the westward propagation of the Tethys in combination with the evolution of the Atlantic Ocean. The region corresponds to the western part of the southern passive margin of the Tethys until the end of Paleogene marine deposition. Though overprinted by alpine collisions in late Tertiary times, the role of such fault trends can be demonstrated all over the region. Comparable fault directions as well as comparable shape and size of isolated fault blocks have been observed in an area extending from Morocco to the Maltese Islands. Vertical and horizontal mo ements including small-scale rotations and their relationship to different stages of plate reorganization will be discussed using examples from Morocco and Tunisia.

The interaction between local fault movements and global sea level changes caused a characteristic facies pattern for different Mesozoic to Cenozoic stages. The distribution of continental red beds, marine shallow water, slope, and/or deep water deposits can be used for the prediction of reservoirs, sources, and seals. Stratigraphic play concepts will be introduced for Jurassic, Cretaceous, and Paleogene rocks.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994