MINERALOGICAL CHARACTERISATION OF CLAY DEPOSIT NEAR IGBILE SOUTHWESTERN NIGERIA

X-ray diffraction is a basic tool in mineralogical analysis of sediments, and in the case of fine grained sediments an essential one. Understanding of rocks composition, the nature of clay mineralogy content and provenance is very important in Basin evaluation. This study therefore focuses on the use of X-ray diffraction to study the clay stone unit exposed along Igbile, southwestern Nigeria. Five clay stone samples were collected following fieldwork in the study area and were subjected to X-ray Diffraction analysis. This was done in order to delineate the associated mineral composition in the rock samples, determine the crystal forms and shape of the mineral and probably provenance of the mineral content. Observations from the result of the X-ray Diffraction indicated peaks with d-spacing range of 1.488Å, 1.63 Å, 1.59 Å, 1.62 Å and 7.17 Å indicative of Kaolinite and d-spacing range of 1.541Å, 1.817 Å, 2.282 Å, 2.458 Å, 3.343 Å and 4.26 Å indicative of quartz as the only significant, minor to moderate abundance minerals in the rock samples. The nature of the kaolinite in the rock samples is suggestive of a transformational and neoformational origin with acid tropical environment where the degree of leaching is probably intensive. The d-spacing and the plane axis values of the kaolinite also indicated Dioctahedral, Trioctahedral and Pinacoid crystal shape with range of forms {001},{060}, {133},{134}and {002}. Similarly the quartz d-spacing and plane axis values suggested Orthorhombic and Trigonal crystal shape with crystal forms {101}, {100}, {112}, {211}, {110}and {102}. In conclusion, the clay deposit exposed in the study area is made up of detrital kaolinite and quartz which are probably sourced from low latitude region in acid tropical high leaching environment.

EVALUATION OF THE AVAILABLE PLANT NUTRIENTS AT DIFFERENT pH LEVELS OF AHOKOR CLAY DEPOSIT LOCATED IN KOGI STATE, NIGERIA.

The nutrient level of Ahokor clay deposit in Kogi State, Nigeria was evaluated with the view of using it as a soil ammendments in soils deficient in plant mineral nutrients. Exchangeable bases (EB), cation exchange capacity (CEC), exchangeable acidity (EA) and percent base saturation were determined at five different pH levels for the top (LT) and bottom layers (LB) of the clay. These parameters were determined at pH4, pH5, pH7, pH8 and pH9 respectively. The exchangeable bases varied with change in pH with optimum values of K+ (1.120 0.300 cmolKg-1) and Na+ (0.701 0.010 cmolKg-1) for LT obtained at pH7 and pH4 respectively, while those of Ca2+ (0.920 0.025 cmolKg-1) and Mg2+ (0.298 0.027 cmolKg-1) were recorded at pH9. Optimum values for the exchangeable bases for the bottom clay (LB) were recorded at pH9 with values of 0.536 0.020 cmolKg-1, 3.522 0.023 cmolKg-1, 1.959 0.020 cmolKg-1 and 0.358 0.036 cmolKg-1 recorded for Na+ , K+, Ca2+ and Mg2+ respectively. The optimum condition for application as soil ammendment was obtained at pH9 as the percent base saturation which indicates that the crystal lattice is occupied with more of the desired base cations was highest at this pH for both layers.