(Online) Analysis of High Resolution Aeromagnetic Data of Birnin Gwari and Environs for Delineation of Gold Mineralization Potential Zones

Abstract

Summary High resolution aeromagnetic data was analysed and interpreted both qualitatively and quantitatively to delineate the occurrence of porphyry mineral deposits (Gold) in Birnin Gwari and environs, North-Western, Nigeria. The Residual Magnetic Intensity (RMI) anomalies extracted were reduced to equator, thereafter enhancement procedures (First Vertical Derivative (FVD), Tilt-angle Derivative (TDR) and Analytical Signal (AS)) were carried out on the resulted reduced to equator grid of the RMI to improve the quality of the aeromagnetic data for better understanding of the subsurface geology. The RMI revealed several geologic structures which are related to dykes/faults striking predominantly in the NS, NNE-SSW, NE-SW and NW-SE directions. Geological structures delineated as high amplitudes in the analytical signal derived map which are the most significant concentration of mineralization zones in the study area established a positive correlation with CET grid analysis while the CET porphyry analysis map highlights high occurrence of circular and near circular features (porphyry like features). The depth estimation applied using analytic signal and Source Parameter imaging (SPI) techniques show comparable results. The depth to the top of the basement sources ranges from 933 to about 2664 m in the study area.