GEOCHEMICAL

This study represents a comparative mineralogical and geochemical evaluation of clay deposits from Igo and Okhoro, located within the Benin Formation of Southern Nigeria, with the aim of determining their industrial suitability and economic potential. Field observations revealed that the Igo clay occurs as reddish to brownish lateritic clay interbedded with sands, whereas the khoro clay is predominantly light grey with brown patches and is more quartz-rich. X-ray Fluorescence (XRF) analysis of the Igo samples shows high concentrations of silica (SiO₂: with mean value 68.57%) and alumina (Al₂O₃: with mean value 22.59%), with relatively low levels of fluxing oxides. In contrast, the Okhoro samples contain lower silica (mean 59.25%), comparable alumina (mean 21.86%), but noticeably higher iron oxide (Fe₂O₃: up to 7.34%) Trace element concentrations in both locations were generally low, indicating minimal impurity influence on industrial applications. The X-ray Diffraction (XRD) data reveal that the Igo clays are dominated by kaolinite (24.5–45%) and quartz (36–62%), with significant amounts of feldspar minerals (orthoclase and albite) and muscovite. Okhoro samples, however, are overwhelmingly quartz-dominated (88.6–98.04%) with only minor kaolinite (0.98–9.42%) and no detectable feldspars, signifying a highly mature, intensely weathered sediment. These mineralogical differences indicate that Igo represents a submature kaolinite-quartz-feldspathic clay, while Okhoro represents a supermature quartzose deposit. Comparisons with industrial specifications show that both clay types meet some requirements for refractory bricks, hough beneficiation is needed to adjust fluxing oxide levels. Igo clays, due to their higher kaolinite content and natural feldspar fluxes, exhibit stronger potential for ceramic applications, including tiles, earthenware, and fillers for paint or rubber after processing. Okhoro clays, because of their extreme quartz dominance , are more suitable as construction fillers, low-grade refractory blends, or materials for brick manufacturing. Overall, the Igo clay deposit displays broader and more economically valuable industrial potential than the Okhoro deposit, which is limited by its mineralogical maturity.

Ten (10) samples collected from six (06) different locations around Dagballa area in Akoko-Edo area, Southern Nigeria, were studied using field, geochemical and petrographical analysis to determine the relative abundance and distribution of major and minor elements present in the samples. The ten (10) samples comprise nine (09) pegmatite samples and one augen gneiss (01)sample which is the host rock are delineated as DA1-10 for easy recognition. Sampling interval for the rock samples varied depending on the aerial extent of each outcrop and fieldenvironmental conditions encountered. DA1 and DA2 were obtained from location 1, DA3 and DA4 from location 2, DA5 and DA6 from location 3, DA7 and DA8 from location 4, DA9 was obtained from location 5 and DA10 was obtained from location 6. The pegmatites in the Dagballa, area occurs as intrusions and is hosted by Augen-Gneiss. There is the presence of a sharp zonation and chilled margin in the first three locations encountered. The estimated contact between the pegmatite and the granite-gneiss is 30m. From thin section analysis, the pegmatites from Dagballa consist of quartz and feldspar minerals with microcline and albite being the dominant feldspar minerals present in most of the samples. Also, muscovite, biotite, opaque and other accessory minerals are present in minute quantities. Composite whole-rock samples were analyzed for major and minor oxides using X-Ray Fluorescence Spectrometer (XRF). The results reveal the pegmatites are very siliceous with SiO2 values of 66.75 wt.% to 74.75 wt.%. Al2O3 values are relatively moderate between14.57 wt.% to 15.61 wt.%. Na2O and K2O abundances are low and ranges between 2.76 wt.% to 5.56 wt.% and 3.50 wt.% to 8.43 wt.% respectively. MgO abundances are generally low (0.05-0.20 wt.%). Fe2O3 abundances are generally low between 0.30-0.47 wt.% with the exception been the abundance (5.82 wt.%) probably obtained from the host rock. Alumina saturation index (A/CNK) computation with values ranging from 1.160 to 1.738 indicates the rock samples are all peraluminous and therefore indicate S-type granite.

Twenty-two samples were collected from Egboha well in Imo Formation, from which ten(10) samples were used to identify the different lithologies, Degree of effervescence were carried out to determine samples with carbonate minerals. Geochemical analyses were also carried out to get the geochemical data using ICP-MS and ICP-OES. Geochemical data for Imo Formation are presented and applied as proxies for deciphering paleo-environment (detrital influx, redox conditions, paleo-productivity) and providing insight to paleo-environmental conditions responsible for sedimentary geochemistry of Imo Formation. The detrital influx proxies used for this work [Si/Al having values ranging from (5.386-2.976) and Ti/Al having values ranging from (0.099-0.061)], show an increase in detrital influx (rate of deposition) and coarse grain at two depths, and at the other depths there is a decrease in detrital influx and fine grain. Paleo-redox proxies used for this work [Mo/Al having values ranging from (0.539-2.429), Ni/Al having values ranging from (7.181-16.194), U/Al having values ranging from (0.467-2.065)], show an enrichment of (U, Mo, Ni) and the oxygen level being suboxic - anoxic environment. Paleo-productivity proxies [Ba/Al having values ranging from (43.088-27.935)] shows an increase in the paleo- productivity at three depths which indicates high productivity of organisms during the Paleocene period, while at other depths, low productivity of organisms can be observed. Paleo-salinity [Sr/Ba having values ranging from (0.065-0.112)] shows an increase in paleo-salinity, which indicates high salt content at two depths and at other depths low paleo-salinity can be observed at
other depths. The result shows that elemental geochemistry can be applied to Study the paleo environment, paleoclimate, and depositional conditions