Pages: (1-10 )
Abstract
Variation in grain size distribution and the intensity of current is significant in determining the pattern of sediment transport, provenace and depositional enviroment. Samples for this study were collected from the Nigeria coastal waters between May to June 2009. The sediments were collected with a grab at water depth of 10-100 m. A total of twenty nine sediment samples were analysed to determine the spatial trend in their textural characteristics. The sediments were mainly silty sand, mud and sand of various sizes. The sediment grain size distribution ranged from fine to medium grained sand, poor to moderately sorted, coarse skewed and with a leptokurtic distribution. The mean grain size varied from 1.85 Ф -2.67 Ф which implies fine to medium grained sand. The sorting values were 0.6 Ф -1.65 Ф representing poor to moderately sorted sand. Skewness value lay between –0.10 and 0.3 Ф while kurtosis was 0.1 - 0.95 Ф. This study showed that sediment along the Lagos coastal water was transported by weak longshore current coupled with slow rate of sedimentation deposited in low energy environment.
Keywords: Textural; Grain size; Longshore current; Sediment; Spatial trend,