Sedimentary Facies and Depositional Environments of Cenozoic Sedimentary Formations Cropping Out at the Central Part of the Douala Basin

Abstract

The Douala Basin is one of three units of the Cameroonian coastal basin in the Gulf of Guinea, formed from the east-west extension between African and South American plates generated during the opening of South Atlantic in the Early Cretaceous. This basin contains sediments from Lower Cretaceous to present. The Cretaceous depositional environments are well understood whereas there is very little information concerning Cenozoic depositional environments. Facies and their stratigraphical distribution analyses were conducted on Cenozoic formations exposed at the E-W central part of the Douala Basin in the Missole II, Piti, Missole I and Dibamba localities, with an objective to provide details on the depositional environments and to reconstruct the depositional model and their evolution over time. Seventeen (17) lithofacies were identified on the basis of lithology, grain size and sedimentary structures. The facies constitute three (3) main facies associations; the gravelly dominated, the sandy dominated and the fine grained dominated. These facies and facies associations were interpreted and five depositional environments successions were recognized; the fluvial-braided and meandered channel, the delta plain, the continental shelf and the marginal-littoral. The facies distribution shows a progradational succession from a fluvial to delta plain at the axial part of the basin and a storm dominated continental shelf to marginal-littoral at the central part of the basin. The facies stacking patterns depict sedimentation mainly controlled by sag subsidence and probably by climate.

High-resolution sequence stratigraphy from well-log patterns and base-level variations of the Paleocene - Early Eocene N’kapa Formation, Douala onshore Basin (SW Cameroon)

“…This surface corresponds to the top of the Middle Paleocene (Selandian), according to the chronostratigraphic chart of Robertson (2015). Bachirou et al (2014) show that at outcrops this surface is represented by ferruginous concretions, with 10 centimeters thick.…”

“…This period is mainly in uenced by tectonic activity which dominated the sea's forward and backward movements (Robertson, 1992 ;Lawrence et al, 2002). A subsidence phase from the Paleocene to the Early Eocene (Ypresian) consists of marine and continental deposits and an uplift phase at the Late Eocene, is composed of clastic shoreline deposits (Bachirou et al, 2014).…”

“…The literature review of these previous works shows controversies related to the depositional sequences and the factors that controlled sedimentary records during the Paleocene-Early Eocene. The rst group of authors (Bachirou et al, 2014 ;Mbesse et al, 2021) present the Paleocene as a transgressive period and the Early Eocene as a regressive period. Contrary, the second group (Mvondo, 2010 ; Kwetche et al, 2018 ;Koah et al, 2021) shows that the Paleocene-Early Eocene of the study area was globally a prograding period, disturbed by the maximum ooding of the Ypresian age.…”

Palaeoenvironment of the Albian‐Cenomanian Mundeck Formation in the Douala Basin (SW, Cameroon): Evidence from facies analysis and geochemistry

“…These deposits were succeeded by the Campanian to Maastrichtian deposits (Logbaba Formation), which consist of basal clayey marls and turbidites. This sedimentary succession is in turn overlain by shales, marls, limestones, fine to coarse-grained, cross-stratified sandstones intercalated with kaolinitic sandstones, bituminous shales and ferruginous sandstones (N'Kapa Formation) dated Palaeocene to Eocene (Mfayakouo et al, 2014(Mfayakouo et al, , 2021Njike Ngaha et al, 2014).…”