Structural analysis of magmatic Ni-Cu sulfide deposit based on high-precision magnetic surveying: A case study of the Baixintan Ni-Cu deposit in eastern Tianshan, NW China

The Baixintan deposit is one of newly discovered magmatic Ni-Cu sulfide deposit in eastern Tianshan nickel belts, NW China. As exploration progresses, the understanding of the whole subsurface structure and unexposed deposits in this area remains insufficient to meet the challenges of deep exploration. In this study, a cost-effective and high-precision ground magnetic surveying was employed to investigate the underground structures of the mining area, primarily due to the frequent presence of ferromagnetic minerals. Utilizing the high-precision magnetic data, the main fault structures were delineated based on robust edge detectors such as horizontal derivative, tilt angle and analytic signal. Additionally, the extensions of the primary mineralization zones and the burial depths of the ore-bearing rock bodies were determined through 3D physical property inversion technology. The target area for ore exploration was defined based on the available geological and drilling information. Our findings suggest that the primary magnetic anomalies in the study area are attributed to shallow geological bodies, specifically those less than 400 m in depth, and their morphology agrees well with the mafic–ultramafic rocks exposed on the surface. The predominant magnetic structures are oriented in the NE-SW and NW-SE directions, of which the NE direction is closely related to mineralization. The Ni-Cu mineralization bearing mafic–ultramafic rocks extends eastward along the NE-trending fault. This study not only enhances mineral exploration efforts in the Baixintan mining area but also serves as a valuable reference for exploring similar deposits covered by the Gobi Desert.