Textural and Compositional Studies of Sediments from Parts of the Albian Bima Sandstone, Upper Benue Trough, Nigeria

Studies were carried out on fresh samples of sandstones from parts of the Bima Sandstone to classify it on thebasis of its textural and compositional characteristics. Grain size analysis of samples reveals that they are fine tocoarse-grained, moderately sorted to poorly sorted, coarse skewed to strongly fine skewed and very platykurticto extremely leptokurtic. Thin-section analysis reveals the sandstones to be lithic subarkoses, subarkoses, andlithic arkoses comprising averagely of 66.6% quartz, 21% feldspar and 12.4% rock fragments. The appreciableamount of feldspar, the dominance of subangular to angular grain shape and the poorly sorted nature of thesandstones suggest that they are texturally and mineralogically immature sediments. Bivariate plots of graphicmean versus standard deviation, skewness versus standard deviation and simple sorting versus simple skewnessindicates a fluvial origin for sandstones deposited under a moderate to high energy level.