Sedimentology and Preliminary Assessment of the Industrial Applications of Shale Facies in the Ogwashi-Asaba Formation, Niger Delta Basin, Nigeria

Abstract

Sedimentological and major element oxide geochemical evaluation of shale facies in the Ogwashi-Asaba Formation outcrops in the Obomkpa area of Niger Delta Basin, was evaluated to preliminarily assess the industrial potentials of shales in this study. To assess the potentials of the shale as raw material for industrial purposes, representative samples obtained from outcrops were subjected to geotechnical and geochemical analyses using conventional wet sieve analysis method, Atterberg Limits and firing tests, and x-ray florescence (XRF). Field and laboratory sedimentological evaluation reveal a dark to black coloured, fissile shale lithology with sand percentages of 1 – 4 % and bed thickness variation of 1.8 – 4 m. Major element oxide wt. % show that SiO2 ranged from 46.78 – 52.45%, (av. = 48.82%) and Al2O3 ranged from 25.33 – 29.82%, (av. = 27.05%) and make up 75.87% of the bulk chemical composition. Although little or no variability exists in the SiO2 and Al2O3 contents between samples from various locations, major oxide variability exists between the shale and those of notable industrial clays. IL/MA ratios suggests disordered kaolinite/illite as the constituent clay mineral present in the shale, while a characterization based on the Cassagrande soils classification scheme revealed inorganic earth material of high compressibility and high plasticity. Fired shrinkage at 950°C and 1000°C and above ranged from 9 – 11% and 5 – 9% respectively. Fired colour change at 950°C and 1000°C and above remained reddish brown. Comparison of analysed properties of the shale with specifications of notable clays, reveal that the shale have potential industrial applications in the manufacture of acid-proof products, sanitary wares and glazing tiles, rubber production, cosmetic, paint and coating material for paper production, if appropriate beneficiation is done to improve their economic and industrial value.