Abstract: The stratigraphy and paelodepositional environment of the Ajaka area were analysed using a detailed study of outcrops. Results show that two major lithostratigraphic units outcrop in the area; dominantly conglomerate unit which can be subdivided into the paraconglomerate and the orthoconglomerate subunits, and the massive sandstone unit. The paraconglomerate consist of matrix-supported, sub rounded to rounded and poorly sorted conglomerate. The paraconglomerate facies is interpreted to have been deposited in a debris flow based on its poor sorting, absence of stratification and lack of fossil. The orthoconglomerate facies are clast-supported, subrounded to rounded, poorly sorted and contain quartz and feldspar. Such framework-support rock that suggests transportation by rolling and accretion of clast along bed. The matrix of very coarse sandstone is thought to have been transported in suspension simultaneously with bed-load rolling of the large clasts. The graded bedding of this facies indicates deposition from a single current as the energy and flow strength diminished. The massive sandstone facies consists of fine-to-coarse grained massive sandstone. The sand grains are angular to subrounded and poorly to moderately sorted. This facies is interpreted to have formed as a result of transport and deposition by short-lived mass flows. Indications from pebble analysis show that the pebbles of the study area were essentially shaped by fluvial process. Sieve analysis of sand-size particles indicates that the sandstone is largely fluvial deposits. The palynological analysis, indicate the presence of Retidiporites miniporatus, Hexaporotricolpites emelianova and Buttinia andreevi, which all are indicative of the Maastrichtian age bracket in the geological time scale. This evidence thus suggests that the outcrops of Ajaka and environs are Maastrichtian in age.
Keywords: Maastrichtian in age, sandstone, Environmental Indications and paraconglomerate.
Title: GEOLOGY AND STRATIGRAPHY OF AJAKA AND ENVIRON IN THE NORTHERN KOGI DISTRICT OF KOGI STATE, NIGERIA
Author: Onyedika H. Nzewi, Tamunoene K.S Abam, Nfor Bruno, Adaora G. Atuchukwu, Ifeoma W. Nnadi
International Journal of Mathematics and Physical Sciences Research
ISSN 2348-5736 (Online)
Research Publish Journals
