Abstract: Paleogeography and Sedimentation in the Douala and Kribi/Campo Basins in Cameroon -- West Africa

Jean-Pierre Loule, Simon Tamfu, Richard Seme Abomo

New biostratigraphic evidences in the Douala and Kribi/Campo basins in Cameroon indicate that communication between the South and central Atlantic oceans was effective in the Cenomanian. This communication led to the deposition of the upper Mundeck formation, which is time equivalent of the prolific Ewongue (Batanga) and Anguille sands of northern Gabon and

the Labe Formation of Cabinda.

The climate in the Cenomanian had evolved from a typical warm and dry (probably arid) type during the pre-Albian to dry with humid influences triggered by the Cenomanian open marine circulation between the central and South Atlantic oceans during the Albian and Cenomanian. It became tropical wet (Ar) during the Senonian to middle Eocene, and tropical wet-and-dry (AW)² from the Oligocene to the Neogene.

Throughout these basins, sedimentation has been dependent upon sea levels fluctuations, thermal isostatic subsidence, local tectonics, and changes in the morphology of the coastline. The Lower Cretaceous sediments consist of synrift coarse sandstones and conglomerates of terrestrial origin, whereas the Upper Cretaceous and Tertiary sedimentary fills consist mainly of fine clastics with thin interbedded carbonates. Active rift tectonics was diachronous, as depicted by two main subsidence phases: the Early Cretaceous phase, observed in the Kribi/Campo region in the south, and the Late Cretaceous-Tertiary phase, found in the Douala region. Subsidence in both cases was accommodated primarily by lithospheric thermal cooling and secondarily by normal faulting.

Paleogeographic reconstructions show that the Sanaga River has been the main feeder of clastics into the Douala and Kribi/Campo basins since the Early Cretaceous.

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