Audio Magnetotelluric Imaging of a Concealed Mineral Deposit: A Case Study of Carbonate Hosted Zhugongtang lead-zinc Deposit, NW Guizhou Province, China

Abstract

Abstract Non-intrusive geophysical exploration methods play a major role in ore deposit detection. This study aimed to characterize the subsurface electrical resistivity structure across the recently discovered super-large Zhugongtang lead-zinc deposit in north-western Guizhou province of China, using audio magnetotellurics (AMT) method. The results of this procedure were compared with available geological information. The estimated geoelectrical strike by impedance tensor invariants ranged between N285°E and N315°E. This range is consistent with known NW-SE trending structures in the Zhugongtang mining area. The obtained 2D inversion models revealed the presence of formations with an exceptionally low resistivity (< 15 Ωm), which corresponded to the known location of lead-zinc bearing formations. Moderate to low resistivity anomalies (< 63 Ωm) were observed at both shallow and greater depths. These anomalies were interpreted as indicative of geological formations composed of shale, sandstone, claystone, and silty mudstone. In addition, the resistivity models also revealed widespread high resistivity anomalies (> 1000 Ωm). These anomalies were thought to represent dolomite and limestone lithologies. In summary, the results presented in this study make a valuable contribution to the existing body of literature on the Zhugongtang deposit.