Sedimentary Facies and Depositional Environments of the Tertiary Kerri-Kerri Formation, Upper Benue Trough, Nigeria

The sedimentary facies of Tertiary Kerri-kerri Formation around Maina Maji and environs was investigated to characterize their depositional facies and infer the depositional environments. Well exposed vertical profiles of the sediments were studied around abandoned mine, erosional channels, cliff drops and on top of hill for some exposures of grain supported conglomerate with special attention focused on their physical, internal and biogenic characteristics. The facies and facies associations in the lithostratigraphic units mapped include conglomerate, sandstone, siltstone and claystone. The conglomerate facies are moderately sorted; grain supported and mature, showing evidence of reworking and recycling. The sandstone facies are commonly compositionally mature, and contain clasts of reworked clays usually white in colour and this suggest high energy tidal channels and shoreface. The associated and kaolinitic claystones are interpreted as braided fluvial channels and floodplain deposits. The sedimentation pattern and characteristics suggest predominance of trangressive shallow marine processes occasionally incised by fluvial channels. The clay deposit associated with the floodplains may offer economic resource potential in the area