Rocks, soils and bed sediments of River Okura catchment area in Anambra basin have been analysed for major oxides using minipal 4 ED version of XRF machine. A total number of five (5) rocks and twenty (20) samples of soil, river bed sediments for each were collected from the study area. These results have been used to characterize and deduce the effect of weathering and transport in the study area. Chemical composition and field studies assessment of the rock(s) in the study area indicated lithic arenite type of sandstone. Results of soils analyses shows a compositional enrichment of Fe2O3 (12.54%) and depletion of Al2O3 (13.74%) when compared to the average crustal compositions of the earth by Clarke and Washington, which have 6.70% Fe2O3 and 15.65% Al2O3. A trend of concentration of major oxides in soils in which: SiO2 > Al2O3 > Fe2O3 and CaO > K2O > Na2O > MgO is the same in all the locations, which strongly suggest that, the soils in the study area are of the same origin and probably a weathered product of the sandstone member of the Ajali Formation derived from the immediate vicinity. Compositionally, the soils in the study area and river bed sediments of Okura River shows similar trend in concentration with the rocks (sandstone) within the catchment area except that, they are enriched in SiO2 and Al2O3, and depleted in Fe2O3 These are obviously due to the complex processes of weathering, ferrugenization, transport (flow) system, purification, accumulation and dilution in the presence of precipitation within the study area.
- bed sediment,
- okura river,
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