Reserve Estimation of Barite Deposits using Geological and Geophysical Investigations in Cross River State South Eastern, Nigeria.

Barite deposits occur mostly as concealed mineralization dominantly in shales and sandstones of Cretaceous age in Cross River State. Vertical Electrical Sounding (VES) and Horizontal Resistivity Profiling (HRP) have been carried out in areas with less mining activities. Also, field geological mapping in which the lengths and the widths of barite veins were measured has been undertaken.The geophysical data collected within 22 communities was done in 52 locations and the results indicate that the barite occurs in veins located at 10 – 12.2m depth and could be up to 40m in open mine pits. The lateral extent of the veins range from 4m to 65m from the from the horizontal resistivity profiling results, and could be traced from the field mapping to about 950m . The  general direction of the barite mineralization is  NE-SW . The result of the reserve estimate indicate that the Agoi village of Oban Massif has 1,981,177.0  metric tons of reserves, these are greater than the reserve found at mamfe embayment villages of Ekukunela and Nkarasi with reserve deposits of about 865, 684 metric tons. These reserves are also greater than those found in parts of the lower Benue trough villages of Osina and Okpoma (Ogoja) with reserve deposits of about 774, 345 metric tons.  An estimated reserve of over nine (9) million metric tons of barite have been calculated and documented for Cross River Stat for the first time. This has unarguably put Cross River State as having the largest reserve of barite in Nigeria. Keywords: Barite, VES, HRP, Reserve, geophysical, mineralization , resistivit

Petrography, geochemistry and industrial quality of the Etono limestone in Ugep Southwest, Southeastern Nigeria

Petrographic and geochemical analyses were carried out on limestones occurring in Etono, Southwest Ugep, Southeastern Nigeria to determine their chemical composition, industrial uses and classification. Samples of limestone in the area were subjected to petrographic study and analyzed geochemically using Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) and X-Ray Fluorescence (XRF) techniques. The petrographic analysis reveals that the Etono limestone contains high percentage of carbonate materials with scanty organic remains and patches of iron. The bulk- rock composition of the limestone shows that the average SiO2 = 9.02%, Al2O3 = 1.95%, Fe2O3 = 2.08%, MgO = 0.39%, K2O = 0.47%, Na2O = 0.00%, CaO = 47.92%, SO2 = 0.24% and LOl = 37.37%. The limestone is classified based on their moderately high CaO, SiO2 and LOl and very low MgO. The mean CaO (47.92%) of Etono Limestone is high relative to the mean CaO of Agoi Ibami Limestone (43.83%) but low relative to the Mfamosing Limestone (55.30%) and the mean SiO2 values of 9.02% is high relative to Mfamosing Limestone (0.38%) but low relative to Agoi Ibami Limestone (13.93%). Results of the geochemical investigation reveal a shallow marine environment of deposition (EOD) for Etono Limestone. The higher values of CaO and LOl and lower values of SiO2 of the limestone suggest that it can be used for cement production, building stone, filler and agricultural purposes