Application of Transient Electromagnetic Method for Mapping Deep-Seated Sulphide-rich Zones in High-Resistivity Settings: A Case Study in Tsauni, Northcentral Nigeria

Abstract

The massive form of base metals in diverse geological settings holds greater economic significance than their disseminated counterparts, necessitating the distinction between massive and disseminated kinds. The sulphide mineralization in the area is recognized as hydrothermal vein-related rather than volcanogenic massive sulphide type, and it is situated in a highly resistive environment which prompted the use of TEM because of its capacity for depth penetration, it reduces electromagnetic coupling, improves resolution, is less sensitive to geological noise, and can acquire data faster; hence, the galvanic approach alone is insufficient for locating deep-seated sulphide-rich zones because of its limitations in current diffusion, electromagnetic coupling and depth limitations. Twenty-two (22) moving loops (Slingram) were established with dimensions of 200m by 200m. Simulations of individual lines conducted with Maxwell software indicated a substantial electromagnetic plate exhibiting a pronounced southerly dip, extensive strike, and significant depth extension. Following the fundamental initial hypothesis, this delineated the conductive structures associated with the deep-seated, sulphide-rich zone. The Tsauni sulphide deposit is observable along a 1 km strike length and demonstrates considerable conductivity indicative of tungsten sulphide potential. This process is particularly evident in regions where the host rock geology exhibits high resistivity; which is highly applicable in mineral Exploration, hydrocarbon Exploration and geothermal Exploration. The greater the resistivity, the more pronounced the induced polarisation relaxation impact on the transient electromagnetic signal.