Grain Size Analysis of Sediments From Okpoama – Brass Beach in the Niger Delta

Abstract

Granulometric analysis was carried out on sixty – three sediment samples collected from the Okpoama – Brass Beach, in the Niger Delta, to determine the particle size distribution, the nature of the sediments and transport mode of the sediments. The sediment population is predominantly unimodal, with the 0.25 – 0.125 mm (fine sand) as the modal class, though, a significant population are polymodal. Sorting ranges from 0.1 (very well sorted for the unimodal samples) to 1.01 (poorly sorted for the polymodal samples). The average sorting value for the entire sampled population is 0.89 (Moderately sorted). The skewness of the population range from symmetrical to negatively skewed. The average values for the kurtosis is 1.2 (Leptokurtic). The average value for the Median (φ) is 1.92 which represents the medium sand size grade, while the average Mean value is 1.95 φ. The predominant mode of transport is by saltation for the modal class, and suspension and traction for the finer and coarser sediments respectively. The sediment load from Okpoama – Brass beach are dominantly fine sands, indicative of distant source rock and a gentle depositional slope.

Keywords: Beach. Grain size analysis, Unimodal, Mean value, Cumulative curve, Saltation.

DOI: 10.7176/JEES/9-3-09

Publication date:March 31^st 2019