GEOCHEMICAL ASSESSMENT OF LIMESTONE DEPOSITS AROUND OMI ALAYO – OKELUSE, SOUTHWESTERN NIGERIA

Limestone deposits exposed at Omi-Alayo and Okeluse Forest Reserve were investigated in this study. 10 representative samples collected from both locations and were subjected to geochemical analyses using X-Ray Fluorescence method. Major and trace elements were employed for the determination of depositional environment. The results for the major oxide contents showed that mean values of CaO content ranges from 48.10 – 48.89% with mean value of 7.23% for SiO2. Fe2O3, MgO and Al2O3 concentration have mean values of 1.56%, 0.76% and 1.92% respectively. Other oxides TiO2, Na2O, K2O and P2O5 are low in concentration. For the loss of ignition, it varied from 35.24 to 41.07 with an average value of 38.69% indicating high carbonate content for the limestone. Limestone classification of Ca/Mg ratio and reciprocal MgO/CaO showed ratios range of 54.05 – 86.46 and 0.011-0.0.024 respectively. High content of Sr recorded for the limestone samples reveals a saline environmental condition for the deposits. Overall results showed that the Omi-Alayo and Okeluse limestone are pure limestone and were deposited in a shallow marine environmental condition and suitable for cement production.