Akinnigbagbe Akintoye E
Cross-shore beach samples from 50 locations at Seme and Yovoyan, Badagry Lagos, were studied to ascertain the variations in grain size distributions along beach profiles perpendicular to the shore. Heavy mineral abundance was also carried out to determine mineral concentartions between sampling Stations on each transect line. Sediment samples were recovered from backstake, berm, slope, water line and control (dark spot) at each Station. The grain size distribution within the beaches is of medium to coarse grain, moderately well sorted which shows transportation under fluvial and tidally influenced medium to high energy conditions. The commonly observed heavy mineral assemblages in the sediments are opaque, rutile, zircon, kyanite, epidote, staurolite, tourmaline and hornblende. The proportion of the heavy mineral fraction was found to be higher in berm and control samples. The distribution of the heavy mineral showed that there is no systematic variation along-shore of heavy mineral species of higher specific gravity but difference in their relative abundance. The mineral species with higher densities such as rutile and staurolite were more in the backstake, berm and control samples. Hornblende was not discovered in the samples recovered at the berm, slope, waterline and the control from Yovoyan, it was only found in the sample obtained at the backstake. This might be that it has been altered to epidote. Occurrence of zircon, tourmaline and rutile in sediment suggest acid igneous, reworked sedimentary and metamorphic rock origin coupled with the presence and low percentage of staurolite, epidote and kyanite which show that the sediment from Seme and Yovoyan beaches could have been principally formed from acid igneous rock, reworked sedimentary rock with minor contribution from medium to high grade metamorphic rock. The ZTR index revealed that the sediments from the backstake and berm are mineralogically more matured.
Published Date: 2020-11-27; Received Date: 2020-07-11