GEOCHEMISTRY AND AGRICULTURAL IMPORTANCE OF MARBLES AROUND IGARRA AREA

ABSTRACT

Marble deposits occur prominently in Igarra area of Southwestern Nigeria. Two representative marble samples collected from Ikpeshi and Igwe minning sites making a total of Four were subjected to geochemical, mineralogical and Calcium Carbonate Equivalent (CCE)) analysis in order to determine their applications in Agriculture as soil conditioner (fertilizer and pH control in soil). The samples were grounded to powder and sieved with sieve Numbers 20, 60 and 100 to determine their fineness. The fineness results combined with the CCE was used to determine the Agricultural Index of the marble samples (Effective Neutralizing Value (ENV)) of the lime. Geochemical data showed that the marbles are characterized by low SiO2 (1.08 – 1.18%), Al2O3 (0.08 – 0.8%) and MgO (1.75- 2.70%) and high CaO (49.96 – 53.64%) and LOI (41.90 – 42.60%) in Igwe, and SiO2 (0.07 – 1.47%), Al2O3 (0.25 – 0.78%) and MgO (0.84- 3.11%) and high CaO (52.80 – 55.90%) and LOI (43.50 – 45.70%) in Ikpeshi. Igwe and Ikpeshi marble recorded low MgCO3 (2.50-12.10%) and high CaCO3 (87.9-97.50%) and high CaCO3 (61.03 – 95.61%) and low values of MgCO3 (1.35 – 7.44%) respectively. The ENV are; Igwe (91.19- 95.88%), Ikpeshi (85.58-95.02%) respectively. From the result, the Agricultural application of these marble is suitable for soil conditioning as well as for fertilizer due to their high neutralizing values. These marbles contain Calcium and Magnessium which are essential major elements for crop growth and also they can increase the pH of acidic soils which are characteristic of tropical soil thereby allowing mobility of essential nutrients to crops.