An aeromagnetic investigation of the Dapai deposit in Fujian Province, South China: structural and mining implications

Abstract The Dapai region is considered as one of the largest polymetallic reserves in Fujian Province, South China. As exploration advances, so does the demand for prospecting the deeper concealed deposits in this place. However, in the past few years, due to the rugged surface topography and dense vegetation, few high-precision and large-scale ground surveys have been carried out in this area. Therefore, the understanding of the overall structure and non-exposed deposits remains insufficient to meet the challenges involved in deeper ore prospecting. In the present study, we applied a cost-effective and high-precision aeromagnetic survey to investigate the structural trends prevailing in the study area and delimit the areas with potential for finding deposits. To achieve the aforementioned goals, the tilt angle derivative was conducted on the pre-processed magnetic anomalies to highlight any deeply seated structural features, based on which reliability of the geologically-inferred faults was analyzed, and seven major faults and 22 minor faults were identified for the first time. Most of these deduced faults show an NS trend in the center part and an NW/NE trend in other parts of the study area. In addition, 3D generalized physical property inversion of the obtained residual magnetic anomalies was implemented to delineate the potential ore bodies, based on which an integrated prospecting target map was established. Our inversion results indicate that there are several isolated magnetic sources in the subsurface extending from a depth of a few hundred meters to no more than 3 km. This presented study not only leads to a deeper understanding of the Dapai deposit, but also provides references for studying other similar deposits where large-scale ground studies are hard to be executed.