Publications scientifiques
Arcange Duviol Tsanga
Gerardine Saurelle Ngokam
Same Moutongo Jacques-David
Victorine Ambassa Bela
Annick Kwewouo Janpou
Armel Zacharie Ekoa Bessa* (Auteur correspondant)
Mohamed Abioui
Autres affiliations : University of Coimbra
John S. Armstrong‐Altrin
Journal of African Earth Sciences
The hinterland of Campo is marked by Archean, Paleoproterozoic, and Cretaceous geological formations. Petrographic, mineralogical and geochemical analyzes of beach sediment samples were performed to determine the origin, alteration, and paleoclimate of the various coastal sediment layers and to reconstruct the structural context of the source region. The beach sediments are fine to medium-grained in size. Morphoscopic examination showed a predominance of very angular and shiny quartz grains. These data reflect a relatively close source with transport in a fluvial environment. The Chemical Index of Alteration (CIA: average = 79.94%), Plagioclase Index of Alteration (PIA: average = 85.31%), as well as the A–CN–K and (A-K)-C-N triangular diagram, show that the weathering affected the source area rocks. The ratios of SiO2/Al2O3, K2O/Na2O, and the chemical composition variation index (ICV ∼ 1.32) show that the sediment samples are immature to mature in terms of texture and chemical composition. Al2O3/TiO2 ratio values ranged from 3.04 to 33.44, indicating an intermediate to felsic rock signature, confirmed by Zr vs TiO2, La/Sc, and Th/Co binary diagrams. Geochemical results reveal a passive marginal continental environment. The passive margin emerged during the opening of the South Atlantic Ocean, which is compatible with the overall geology and structural setting of the studied area.
