Linking mineralization styles to pyrite geochemistry: Implications for ore genesis and exploration in the Jiaojia gold deposit, Jiaodong Peninsula, China

The giant Jiaojia gold deposit (>200 t Au) in the Jiaodong Peninsula, China, hosts three distinct mineralization styles: disseminated, breccia, and stockwork (orebodies I and II); thin pyrite-muscovite-quartz veins (orebody III); and auriferous quartz-sulfide veins (orebody IV). These styles are spatially controlled by a multiorder fault network. Integrated in situ textural, trace-element, and sulfur isotope analyses of pyrite reveal that these styles formed during a single hydrothermal event, with gold precipitation mechanisms varying systematically with structural setting. In the high-strain fault core and damage zone of the Jiaojia fault zone (orebodies I and II), extensive fluid-rock interaction and sulfidation dominated, producing pyrite enriched in Ag, As, Au, Bi, Cu, Pb, Sb, and Te, with heavier δ34S values (median 10.95‰) relative to those in orebodies III and IV. In contrast, steep faults within the secondary Baoli fault zone hosting orebody IV record lighter δ34S values (median 9.48‰) and porous pyrite with elevated Au/As ratios and broad trace-element variability, indicating rapid crystallization from fluids that underwent intense phase separation triggered by abrupt pressure drops. Orebody III, hosted in the transitional zone, displays mixed geochemical and isotopic characteristics, reflecting contributions from both sulfidation and phase separation. Overlapping homogenization temperatures of fluid inclusions from previous studies across orebodies rule out significant thermal gradients, demonstrating that fault zone architecture, by modulating sulfidation and fluid depressurization, was the primary control on gold precipitation. These findings establish a genetic model directly linking specific ore styles to their structural domains, providing a predictive framework for exploration.