Northern Algeria: Geodynamic Evolution and Petroleum Prospectivity

Bracene, R., Sonatrach, Boumerdes, Algeria

This study outlines the geodynamic evolution, structural framework and petroleum prospectivity of northern Algeria. During the Mesozoic, northern Algeria was part of the southern Tethyan passive margin. From Triassic to present, its geodynamic evolution con­sisted of rift, post rift and convergent regimes.

Rifting took place during the Triassic and Liassic. The margin was characterized by tilted blocks, bordered by NE-SW trending normal faults. The Liassic rifting episode was associated with Triassic salt mobility that generated salt pillows and diapirs.

Post-rift thermal subsidence occurred from the Middle Jurassic to Late Cretaceous, however, extensional events continued in eastern Algeria and the Tell margin.

Convergence and compression occurred from the Tertiary to the present. The spatial and temporal distribution of deformation can be used to identify periods of strong and weak coupling between the African and European plates.

The structural framework consists of several domains. We illustrate the structural rela­tionships between them, present a crustal-scale section and correlate geodynamic events and subsidence phases.

The geodynamic evolution controlled the development of several petroleum systems. Proven Cretaceous and Tertiary petroleum systems have produced hydrocarbons in north­eastern, central and western Algeria. These discoveries are related to Miocene and Quaternary thrust systems that are developed laterally and not yet fully explored. Other petroleum systems, linked to tilted blocks and diapirs of the rift and post-rift regimes, have also developed. This variety of potential petroleum systems widens the areas of prospectiv­ity and hold a promise for other hydrocarbon plays in the northern Algeria.