Geology and Structural Analysis of Oke-Ogun Pegmatite Field Aided By ASTER Data Imagery

Abstract

The growing demand for lithium ion and lithium alloy batteries, due to the worldwide adoption of alternative energies and electric vehicles, has intensified exploration for lithium deposits especially in lithium bearing pegmatites. Low cost remote sensing techniques were used for lithium exploration through lithological discrimination to spectral mineral mapping methods. Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) IT data were used for litho-structural mapping of the east of Saki and North of Komu, Oke-Ogun area of Oyo State, South West of Nigeria. Lithological mapping was achieved in two ways; preliminary mapping using False Colour Composite (FCC) of decorrelation stretch of thermal bands 13, 12 and 10 of ASTER in RGB order, plus spectral reflectance and absorption of Biotite and Hornblende, Enstatite and Hypersthene, Kaolin and Orthoclase. The extracted lithologies were validated using Kappa coefficient by comparing field observation with the lithologies. Band ratios B7/B6 and B2/B4, from spectral reflectance curve of spodumene, were used for Li prospect mapping. Only B7/B6 mapped out pegmatites hosting spodumene. However, B2/B4 gave a better result for Li ore. XRF analysis of pegmatite samples from areas with high prospect for lithium gave lithium oxide (Li O) concentration of 2 7.20%.