Sedimentology, paleoenvironments and provenances of the clastic sequence of the Gombe sandstone around Gombe and environs in the Gongola arm of the upper Benue trough Nigeria

Abstract

The textural parameters computed from granulometric analysis for twenty-five samples of the Gombe Sandstone i.e. graphic mean size, standard deviation, skewness, and kurtosis yielded average values of 2.25ø, 1.17ø, 0.25ø and 1.00ø respectively. Both granulometric and petrographic analysis indicated that the Gombe Sandstone is dominantly poorly sorted and are mostly positively skewed. The sediments range from quartzwacke to subarkose. The bivariate plots of standard deviation vs. mean, standard deviation vs. skewness, standard deviation vs. first percentile and the C–M pattern yielded a dominance of fluvial environment, however, mean vs. first percentile showed a dominance of coastal environment. The probability curve plots showed a dominance of two sand population plots indicating prevalence of unidirectional currents.
Paleocurrent analysis has shown that the Gombe Sandstone trends in the northwestern and southeastern directions with unidirectional current systems, having unimodal distribution, indicating a source from the northeastern and southeastern direction.