Sedimentologic, Heavy Mineral and Provenance Studies of the Cretaceous Sediments in the Auchi Area of the Anambra Basin

Abstract

The Upper Cretaceous Deposits of the Anambra Basin has a part of its sedimentary rock deposited in the Auchi area of Edo State. Geologic field and Sedimentological studies carried out on twenty eight (28) selected samples from a section of a road–cut show that the sediments range from fine through medium to coarse grained. Morphoscopic studies reveal subangular to subrounded outline of sand particles. These coupled with the  various colours observed in the sediment, ranging from whitish sand through yellowish brown, pink and reddish brown possibly indicate a non–marine environment and a fluviatile to deltaic environment of sedimentation is suggested. Heavy mineral assemblage made up mainly of opaque, andalusite, zircon, hornblend, sphene and epidote suggest derivation from the Precambrian Igneous and medium to high grade metamorphic rocks of the underlying Basement Complex of Nigeria.

Keywords: Sedimentology, Cretaceous, Morphoscopic, Heavy Mineral, Provenance