Geological and Geoelectrical Prospecting for Manganese Ore within Tashan-Kade in Tegina Sheet 142, North-Central Nigeria

Abstract

Although manganese has attained the status of elements in critical global demand, the deposit in Tashan-Kade has remained hitherto unreported and yet to be appraised. This study is a preliminary attempt to appraise the deposit by delineating its surface spatial extent and ascertaining its subsurface thickness, through surface lithologic mapping and 2D geoelectrical prospecting. The 2D geoelectrical data was acquired with ABEM Terrameter (SAS 4000) and twenty one etal electrodes arrange Werner field array, along a 100 m long traverse oriented along outcrop foliation dip direction. The geoelectrical data comprised electrical resistivity (ER) and induced polarization (IP) measurements. The data was processed and interpreted using RES2DINV software. The lithologic outcrops are migmatitic schist, amphibolites, granite and manganese ore. The migmatitic schist and amphibolites strike NW-SE and dip 30°W. Broken particles of the migmatitic schist are attracted by a horse shoe magnet, indicating magnetite content. Samples of the manganese ore were inert to dilute mineral acids, thereby precluding rhodochrosite. The ore shows a schistose texture and a sooty residue, which are indications of pyrolusite. The 2D inverse ER and IP models respectively reveal ER values lower than 200 £2m and IP values higher than 2 ms in the western part of the traverse. The geoelectrical values agree with observations of rubbles of manganese ore outcrops on the western part of the traverse. The ER and IP values are respectively lower than 80 2m and 2 ms where the outcrops of the ore bodies are continuous sheet-like bodies. A surface spatial extent of 540,000 m² of manganese ore deposit was delineated between longitudes E 6 11 45 to E 6°12' 00' and latitudes N 108 10' to N 109 00, from inferred subsurface extension captured from 2D geoelectrical models and outcrop locations of the ore. The spatial area and 8 m mean subsurface ore thickness obtained from the 2D geoelectrical models constitute 4, 320,000 m² gross volume for the ore deposit.