Provenance studies through petrography and heavy mineral analysis of part of Agbaja-Lokoja formation, Bida basin, NW Nigeria

Abstract

Fifty five sandstone samples of Lokoja and Agbaja Formations were collected for textural, geochemical, petrographic and heavy minerals analysis with a view to determining the provenance of the sedimentary rocks.The texture of Lokoja Sandstones reveals poorly sorted sub-arkose immature sandstone with the quartz showing both monocrystalline and polycrystalline crystal forms with more of the undulatory forms which depict its derivation mainly from metamorphic origin. Abundance of feldspathic grains is a reflection of its closeness to the provenance which is perhaps located in the north central basement domain on account of the paleocurrent azimuth trend towards the southeast. The conglomerate and sandstone facies are mostly restricted to the Lokoja area. The ironstone mainly found at Agbaja was identified in Oolitic form. The iron rich sediments must have been derived from the rocks of the northern basements, which had been transported to the environment of deposition, as azimuth of primary structure indicate southwardly direction.

Keyword: Agbaja-Lokoja Formation, Heavy Minerals, Petrography, Sedimentology, Provenance