Stream Sediment Geochemistry of Telemu and its Environs: A Tool in Baseline Assessment of Mineralization Potential

Abstract

Reconnaissance stream sediment geochemical studies were carried out in Telemu-Awo-Ede areas of Osun State to determine the concentrations and distribution patterns of trace elements. This was with a view to assessing the mineralization potential of the study area.

Ninety six active stream sediments were collected from stream channels in Telemu-Awo-Ede. The samples were air-dried and sieved. One gram each of the minus 177 micron fraction was subjected to hot acid extraction with aqua regia (3 HCl: 1 HNO₃) and perchloric acid (HClO₄) in ratio 2:1. The aliquots were analyzed for Mo, Co, Cd, Ta, Cr, Cu, Fe, U, Th, Sc, Zn, Sr, La, Mn, Ni, Pb, Sn and Zn using the Buck 205 Atomic Absorption Spectrometer (AAS) interfaced with Graphite Furnace. The geochemical data was interpreted using both univariate and multivariate statistical methods. The element distribution and smoothed contour maps were plotted using ArcView-GIS and Geosoft Oasis Montaj Software, respectively.

The results showed that only four (4) elements out of the eighteen (18) elements analyzed showed significant anomalous values. The anomalies of Sn, Sc, Ta, and Th were considered to be derived from primary mineralization of these elements. Those of Mn, Zn, Cd, and Fe are interpreted as being caused by secondary environmental controls, notably, precipitation of Mn-oxides in the soils and or anthropogenic contamination for Zn and Cd. Insignificant anomalies were observed from Ni, Cr, La, Mo, Pb, Cu Co, U, Sb and Sr.

The study concluded that this area has Sc-Sn-Ta and Th mineralization potentials related to the pegmatoids. The results obtained from the geochemical studies confirmed the heterogeneous nature of the underlying rocks. Areas underlain by pegmatites and pegmatised schist coincide spatially with zones of relatively high values for U, Th, La, Sc, Sn and Ta; and are suspected to be mineralized in tin, scandium, thorium and tantalum.

Keywords: Mineralisation potential, significant anomalies, insignificant anomalies, environmental controls.