The Sedimentology and Provenance Studies of Stream Sediments from Edunabon Area and its Environs, Southwestern Nigeria

C. C. Igwe and M. B. Salami
Obafemi Awolowo University, Ile-Ife, Nigeria

The sedimentological study of river sediments was carried out on the Edunabon area and its environs in parts of the Southwestern Nigeria. The area of study is located between longitudes 7 30'N and 7 36'N and latitudes 4 26'E and 4 30'E on the topographic map of Iwo Sheet 242. 32 samples were collected from different streams and subjected to grain size analysis to determine their sedimentological characteristics. Their provenance was also deduced from their heavy mineral constituents. The grain size analyses data were used to determine the graphic mean, the inclusive graphic skewness and measure of kurtosis, the bivirate plots were used to distinguish the depositional environment. Results from these statistical parameters show that the textural characteristics of these sediments range from coarse grained to medium grained, with inclusive graphic mean values ranging from 0.37-1.93. 81% of the sediments were poorly sorted while 13% and 6% of the sediments were moderately sorted and moderately well sorted respectively, kurtosis values of these sediments range from very platykurtic to leptokurtic. The identified heavy minerals are opaque minerals, amphibolite, staurolite, zircon, tourmaline, garnet, kyanite and biotite. They indicate that igneous as well as metamorphic rock of the Nigerian basement complex are the source rocks for these sediments. The subangular to subrounded forms of most of these mineral indicate a short distance of transportation Deductions from the bivirate plots are consistent with those of earlier workers who studied river sediments.