• MT section images the magma mineral system. • Summarized the role of Gandongbei Fault (GDBF) in the process of shallow surface mineralization. • The first proposed the deep metallogenic background and process model in the Dexing ore concentration area, southeastern China. The Dexing ore concentration area is one of China’s most significant Cu-Au metallogenic belts; however, the genetic origin of its Cu-Au mineralization remains debated. Proposed genetic models include subduction-related slab partial melting, lower crustal delamination, and contrasting interpretations of magmatic versus non-magmatic fluid processes. To address these issues, this study integrates deep electrical structure data from the Dexing ore concentration area with Archie’s law (to estimate crustal fluid fraction), and the Kruse function (to derive pressure gradients), all within a mineral system framework that synthesizes existing geophysical and geochemical datasets. We propose a unified ore-forming fluid migration model to constrain the sources and transport pathways of Cu-Au mineralizing fluids. Our model indicates that the Neoproterozoic orogeny estiablished the primary structural framework and generated a juvenile, metal-enriched crust favorable for Cu-Au mineralization. During this event, Au mineralization was predominantly controlled by upper- to middle-crustal ductile deformation, expressed as: (1) NW-trending ductile nappes hosting ultramylonite-type Au deposits, and (2) NE-trending strike-slip shear zones that localized quartz-vein Au mineralization. In contrast, Mesozoic Cu mineralization was ultimately triggered by the reactivation of the Gandongbei Fault (GDBF). Deep-seated, lower-crustal fluids ascended along the GDBF, resulting in large-scale copper deposition. The evolution of the Dexing Cu-Au mineral system comprises four stages: (1) generation of a metal-enriched juvenile crust and early structures framework; (2) development of NW-directed ductile nappe, localizing initial Au mineralization (∼ 840 Ma); (3) NE-trending strike-slip faulting that remobilized Au into quartz veins (∼ 750–710 Ma); and (4) Mesozoic reactivation of the GDBF, which channeled lower-crustal, Cu-bearing fluids (∼ 171–176 Ma).
Yan et al. (Fri,) studied this question.