Ambient noise tomography reveals deep ore-forming structures of shear zone-type gold deposits at Dongchuan, Kunming Province, China

Abstract

While fault systems constitute the critical plumbing systems in hydrothermal shear zone-hosted gold systems, their spatial architecture commonly remains poorly documented thus limiting the development of robust exploration models. This study investigates the deep-seated fault systems and ore-forming processes in the Dongchuan gold mining area using ambient noise tomography and seismic velocity analysis. A Shear wave velocity model reveals significant lateral heterogeneity, with low-velocity zones corresponding to fault zones, while high-velocity anomalies are associated with deeper magmatic intrusions. The detailed analysis of fault systems highlights their critical role in controlling the gold mineralization, as reflected by distinct high-velocity seismic anomalies. Our study clearly links the spatial distribution of gold deposits to brittle-ductile shear zones, suggesting that secondary faults facilitate the migration of magmatic hydrothermal fluids, contributing to the formation of gold mineralization. Our findings suggest a poly-phase nature nature of the metallogenic process, with contributions from magmatic, and mantle plume events. This study provides valuable insights into the structural controls and fluid migration pathways associated with shear zone-hosted gold deposits.