SEDIMENTARY CHARACTERISTICS OF INYI SAND DEPOSIT AND ENVIRONS IN OJI RIVER, ENUGU STATE, SOUTHEASTERN NIGERIA

Abstract

An intensive field mapping was done, aimed at studying the sedimentological characteristic of Lithologies exposed in Inyi and Environs in Oji River Local Government Area, Enugu State, Nigeria. It was observed that Inyi has two major lithologies, The Shale with a coal seam at the base and some mudstones and clay as the first unit and the Sandstone with presence of pebbles as the second unit. This study led to evaluation of paleo current analysis and textural parameters used to reconstruct the environment of deposition. Integrated paleo-current analysis of foreset cross-beds of Ajali Sandstone orienting in NNE – SSW direction of flow reveals a unimodal pattern which indicates fluvial process of deposition. A total of five sand samples were collected for this study from four locations based on their stratigraphic position (i.e. from bottom to top). Statistics reveals  mean ranges from 0.183 to 2.552, sorting range from 0.187 to 0.732, skewness range from 0.770 to -0.014, and kurtosis between 4.098 and 1.216. The sandstones are false bedded and burrowed, medium to fine grained, poorly to moderately sorted, strongly positively to negatively skewed and platykurtic to mesokurtic. Bivariate and multivariate results reveals that the Ajali sandstones may have been deposited at fluvial to shallow marine environments.