Litho-Geochemistry, Petrogenesis and Mineralisation Potential of Amphibolite-Schists Around Gadaeregi Area, North-Central Nigeria

Abstract

This study investigated the geochemical compositions of Amphibolite-schists around Gadaeregi area of North-Central Nigeria to establish the petrogenetic evolution, geotectonic setting and associated potential mineralization. It was carried out across an area of 134.4km² within Bida sheet 184 NE on a scale of 1: 25, 000. The area is bounded by latitudes 9^o 22ꞌ 00ꞌꞌN - 9^o 28ꞌ 00ꞌꞌN and longitudes 6^o 17ꞌ 00ꞌꞌE - 6^o 24ꞌ 00ꞌꞌE. Systematic field investigation was carried out which revealed that the area is underlain majorly by migmatite-gneiss, amphibolite-schist and granite. Ten (10) samples of amphibolite-schist were subjected to geochemical analysis with reference to major oxide and trace elements using X-ray fluorescence (XRF). Plotting the geochemical results on typical discrimination diagrams revealed that the amphibolite-schists are of calc-alkaline and tholeiitic affinity. It shows a sedimentary origin, basaltic/andesitic progenitor and mixed (continental and oceanic) tectonic setting. Furthermore, the mineralization potential of the area was noted by comparing the result of trace elements in this study with their respective established crustal abundances, hence, Pb, Ag, Bi, Hg, Re, Pd, Ru and Au showed considerable anomalous concentrations in all/or some of the samples, though Au showed highest anomalies. This agrees with the fact that potential mineralization of Au is generally high within the schist belts of Nigeria. It is highly recommended that high resolution sampling at a larger scale be made to delineate the points with high prospects.

Keywords: Gadaeregi, Amphibolite-Schist, Geochemistry