Provenance and paleoenvironmental studies of Bima and Dukul Formations in the Yola Basin, Northern Benue Trough, Nigeria.

Abstract

Sedimentological studies of some areas located within latitudes 11035’E & 12000’E, and longitudes 9014’N & 9025’N were undertaken to delineate the surface lithologies of the Yola sub-basin, in the Northern Benue Trough. Field observations of the surficial deposits at Mayolope, Taana, Kpasam and Bille revealed that they are Bima Formation while the ones in Abare are Dukul Formation. Paleoenvironmental studies based on the characteristics of lithofacies of these exposed sections and laboratory assessments of some selected samples showed that the Bima Formation was deposited in a continental setting while the Dukul Formation was deposited in a low-energy marine setting. Petrographic studies of framework components showed that the samples of the Bima Formation were predominated by quartz minerals, leading to their identifications as sandstones and classifications as quartzarenites while the samples of the Dukul Formation were limestones and were classified as bioclastic packstones. Heavy mineral compositions of the sandstones revealed their provenance; Zircon and Tourmaline with a combined amount of 60.1% suggested igneous and low-grade metamorphic rocks while rutile and staurolite with a total amount of 27.7% indicated contributions from high-grade metamorphic rocks.