Explorations of gold and lead-zinc deposits using a magnetotelluric method: Case studies in the Tianshan-Xingmeng Orogenic Belt of Northern China

Abstract

The Tianshan-Xingmeng Orogenic Belt (TXOB) is located in China’s northern region, and is one of the country’s most important Au-Pb-Zn-Ag-Mo-Cu metallogenic belts. This metallogenic belt is known to have good minerogenetic conditions and exploration potential. However, the engineering detection depths of the majority of the metal deposits are generally less than 300 m. Therefore, high precision geophysical detection techniques are necessary to achieve the required accurate detection results. Among the commonly used techniques, the Stratagem EH4 system has been found to be the better choice for the deep prospecting of the metal deposits in the TXOB. Furthermore, a good understanding of the physical characteristics of the different rock formations in the region is essential for effective and efficient geophysical prospecting. This study revealed that the resistivity values of the ore and rock formation walls were different. In previous related research, the EH4 Conductivity Image System, which is a system combining MT and CSAMT, has been successfully used for ore explorations in China. The results of the geophysical prospecting processes indicated that there was good exploration potential of the aforementioned system in the TXOB.In the current study, the hidden gold ore bodies of disseminated (altered rock-type) gold deposits within the study area were defined by resistivity values of less than 150–1000 Ωm. The concealed gold orebodies in the quartz-type gold deposits were confirmed by resistivity values of 300 Ωm. The mineralization anomalies of the epigenetic lead-zinc deposits were defined by the smaller resistivity values, which were lower than the 100–1000 Ωm range.