GEOLOGICAL, MINERALOGICAL AND GEOCHEMICAL CHARACTERISATION OF THE ILUHAGBA MARBLE DEPOSIT, SOUTHEASTERN ISANLU, CENTRAL NIGERIA: IMPLICATIONS FOR INDUSTRIAL APPLICATIONS
Abstract
Marble, a metamorphosed limestone, is a critical raw material used in constructions, production of cement and soil improvement additives globally. In Nigeria, marble occurs as relict carbonate within the “Pan-African” (late Proterozoic) migmatite-gneiss-schist complex, such as the Isanlu region, central Nigeria. The economic viability of the Iluhagba marble deposit in the southeastern part of Isanlu Sheet 225 SE (part of the basement complex of central Nigeria) was investigated using geological mapping, mineralogical, and geochemical techniques. Six representative marble samples were studied with regard to their mineralogy and geochemistry using X-ray diffraction (XRD) and X-ray fluorescence (XRF). Geological mapping revealed that the study area consists of five major lithologic units: schist (35%), quartzite (35%), granite (18%), pegmatite (5%), and marble (7%). The marble deposits intrude concordantly into the schist (The marble deposits comformably associated with the schist), which strikes in a NE-SW direction and dips to the west. A rose plot shows a principal trend of NW-SE. XRD analysis revealed calcite, orthoclase and quartz are the major components of the marble, indicating that it is a calcitic type. Geochemical (XRF) results showed that major oxides include SiO2 (1.33%), Al2O3 (2.16%), CaO (52.30%), MgO (1.25%) and others less than 1%, while trace elements include Zr (1925 ppm), V (366.67ppm), Ba (676.67 ppm), and Cu (421.67 ppm), reflecting high concentrations (compared to previously reported standards). Elevated zircon suggests that the marble may have been derived from metamorphism of detrital grains in the limestone protolith that probably has a sedimentary origin. The mineralogical and chemical attributes of the investigated marble samples suggest their potential for a wide range of industrial applications, including decorative construction materials, beet sugar production, paints and fillers, pesticides, metallurgical lime and sewage treatment. However, the marble is not recommended for direct cement production unless upgraded due to its low silica content.