Ancient Environment, Sedimentological Characteristics and Mechanism of Transport of Campanian - Maastritchian Sandstone, Lokoja Formation, Bida Basin, Nigeria

Abstract

The Campanian - Maastritchian Sandstone, Lokoja Bassange Formation, Bida Basin, was studied to decipher
its ancient environment, the mechanism of transport and the sedimentological characteristics of the sandstone.
The results of grain size analysis show that the sandstone has medium-sized grains that are leptokurtic to
extremely leptokurtic, moderately well-sorted to moderately sorted, and primarily near symmetrical to coarsely
skew. The medium-grained sediments imply that grains have been transported over a considerable distance. The
near symmetry of the sediments suggests that the processes of erosion and deposition are almost in equilibrium
with one another. Leptokurtic grains predominate in the sandstone, indicating compositionally immature and a
texturally mature sandstone. The coarse positive skewedness indicates a fluvial (non-beach) paleoenvironment
origin. Also, the sorting of Ifon Sandstone at Uzebba and Ori-Ohin ranges from 0.54-1.26(0.90 average) and
0.62-1.42 (1.0. average) which are both of fluvial origin, after Folk’ environmental classification. The results
from the environmental discrimination plots which indicate an ancient fluvial depositional environment. The
mechanism of transportation reveals that the sediments were moved and deposited by rolling, bottom
suspension, and rolling, which are indicative of a high-energy, turbulent environment with high wave activity
and tractive current deposits.