Geology, Mineralogy and Geochemistry of ClayOccurrences within the Northern AnambraBasin, Nigeria

摘要

Clay occurrences at Aloji, Udane Biomi, Ofe-jiji and Agbenema, within Northern Anambra Basin were characterized mineralogically and geochemically in order to investigate its compositional characteristics and petrogenesis. Mineralogical analysis portrays kaolinite as the only observable clay mineral.Abundances of major oxides show that SiO2 (69.67 – 90.28%) and Al2O3 (5.10 – 15.24%) constitute over 76% of the bulk chemical compositions, the high content of Si02 shows that the source rocks are rich in quartz and silica-rich minerals confirming the grittiness of the clay. Other oxides are present in relatively very small amounts. The occurrences of Ca0, Na0 and K20 which are the major components of feldspar in clay suggest the clay to be of granitic origin possibly from Oban Massif, east of the Anambra Basin.Although notable disparities exist in the SiO2 and Al2O3 contents of the clays, the Udane Biomi is more siliceous and less aluminous than the others whereas, the Aloji clay is more aluminous than others confirming a high degree of weathering activities.Evaluation of the clays based on their mineralogical and geochemical characteristics revealed that they are suitable for the production of refractory bricks only.