The sequence stratigraphic analysis of the Sergipe Alagoas, Douala, Rio Muni, and Gabon sedimentary basins shows many similarities and some differences for the Aptian-Albian interval in these different basins. The formation of these basins began in the early Cretaceous, about 123 Ma, when the first sediments accumulated at the opening of the South Atlantic Ocean, south of the Gabon and Alagoas basins. The propagation of the same rifting played an important role in the evolution of each basin along the South Atlantic margin. The main similarities between these basins include the depositional character and the distribution of the sediments of the Cretaceous interval. These similarities depended on the propagation and the evolution of the African-South American rifting and are divided into syn-rift, transitional, and post-rift intervals in the Sergipe-Alagoas basin (located in the northeastern coast of Atlantic Ocean, Brazilian margin), and in Douala, Rio Muni, and Gabon sedimentary basins (located on the western coast of the Atlantic Ocean, African margin).

        The development of the Brazilian and West African passive margins is closely related to the break-up of the super continent Gondwana. The expansion of Gondwana’s rupture had an important role in the Cretaceous interval of the South Atlantic Ocean. The Cretaceous interval of Sergipe Alagoas, Douala, Rio Muni, and Gabon basins contains fluvial lacustrine, evaporates, and carbonate clastic sequences. The lacustrine sequence occupies the syn-rift interval of these basins. This sequence has its origin in the restricted Atlantic Ocean and in the small lakes that were formed along the rifted surface between Africa and South America from late Jurassic until the Cretaceous time.

        Evaporites form the transitional sequence of the South Atlantic Ocean. This sequence lies between syn-rift and post-rift intervals. The carbonate and siliciclastic materials are the most typical sequences of the post-rift interval of the South Atlantic Ocean. These sequences overlie the Aptian salt formation of the Brazilian, Rio Muni, and Gabon basins.

Map showing the locations of Sergipe Alagoas, Douala, Rio Muni, and Gabon sedimentary basins

 

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Department of Geological Sciences

Maintained by Alfredo Ovono Oba.   Last updated 1 May 2001