Numerical simulation of fault-fold structures controlled ore formation: Case studies of the Huize and Maoping lead-zinc deposits in Northeastern Yunnan Province, southwest China

Abstract

Understanding the intricate relationship between fault-fold structures and ore body localization is paramount in economic geology. However, there is a lack of quantitative data on the influence of the geometry characteristics of faulted fold structures on the migration of ore-forming fluids. In this study, the differential ore-controlling characteristics of the steep flank of the anticline (Huize fault-fold belt,the ore body is located in the SE flank of the anticline) and the overturned flank of the anticline(Maoping fault-fold belt, the ore body is located in the NW flank of the anticline) were studied by using multi-physical finite element numerical simulation method. The findings of the study indicate that:(1) The local pressure anomalies in the core and southeastern flank of the Huize fault-fold belt is relatively higher than in comparable elevations elsewhere, while pressure anomalies in the Maoping fault-fold belt are concentrated in the core of the folds. (2) In the internal fault-fold belt of Huize, there is no significant temperature difference on either side of the folds. However, in the Maoping fault-fold belt, after reaching the core, heat predominantly transfers to the top pressure anomaly zone, resulting in noticeably higher temperatures in the northwest flank compared to the southeast flank. (3) Within the Huize fault-fold belt, ore-bearing fluids initially migrate along the fault, then move towards the core and SE flank upon reaching the mineralized strata. In contrast, within the Maoping fault-fold belt, ore-bearing fluids, after entering the layers, primarily migrate towards the core. (4) In the Huize ore deposit, the concentration of Zn2+ is significantly higher in the SE flank than in the NW flank, while in the Maoping deposit, the concentration is higher in the NW flank. The research results align with geological facts and provides valuable insights into the quantitative analysis of ore distribution controlled by the fault structure. This study provides crucial insights into exploring the control and influence of differential structural deformation on ore-bearing fluid migration, offering favorable exploration targets.