Evidence of deltaic système, type Colorado, in the middle terme of the Proterozoic basin of Sembe-Ouesso : Northwest part of Republic of Congo.
The Proterozoic basin of Sembe-Ouesso is located in the northwest part of the Republic of Congo. This basin is the least studied of the basins in the Congolese territory. The geological studies done in this basin are very old, basic or summary and generally oriented to the mining prospecting. No one of them doesn't evoke clearly the sedimentology, the organization and the evolution of the deposit sequences, the paleogeography and the paleoenvironments of the sedimentary formations covering this basin. The detrital formations appear in the sector of Mekoum and Biessi, belong stratigraphically to the middle term calls « greso-pelitique ». The results of our study show that sedimentologically and sequentially, the sedimentation is essentially detrital and organized into three units corresponding to the three environments of the delta : Unit I corresponding to the prodelta, is constituted by an alternance of sandy clay and fine layers of very fine to fine sandstone; Unit II corresponding to the delta front, is constituted by thick beds of medium to coarse sandstone with curve stratifications, interbedded by fine layers of sandy clay ; Unit III corresponding to the fluvial channel is constituted by coarse sandstone with cross strafications. The vertical mega sequence is offlap sequence and is composed of coarsening up elementary sequences. The delta was dominated by tides such as the Colorado delta as describe by Calloway and Hobday (1983). The source of sediments was located to the west of the bassin from the archean basement of Ivindo. The center of the basin was located beyond Mékoum where fine sediments are dominant. The “greso-pelitique” constitutes then a unique deltaic sedimentary assemblage.
Auteur(s) : MIYOUNA T., Malounguila-Nganga D.M., Essouli O.F., Kinga Mouzeo, Kaya F., SOW E. H. & Boudzoumou F.
Pages : 79-94
Année de publication : 2015
Revue : Asian Academic Research Journal of Multidisciplinary
N° de volume : 2
Type : Article
Mise en ligne par : SOW El Hadji