Abstract:

Yangshan gold deposit is located in Wenxian County, Gansu Province.Geochronology study shows that three magmatichydrothermal events happened in the ore district respectively in Early Jurassic, Early Cretaceous and Early Tertiary.Stable isotope analysis shows that δD value of fluid inclusions in mineralized quartz veinlet ranges from-75‰ to-56‰, δ¹⁸O_H2O value ranges from 3.7‰ to 12.2‰, and δ³⁴S value of pyrite and stibnite ranges from-2.2‰ to-0.7‰, indicating that metallogenic materials and ore fluid are mainly from the magmatic events.Analysis of tectonic deformation indicates that ductile deformation occurred in Triassic Period, ductile-brittle deformation occurred in Early Jurassic, while brittle deformation occurred after Jurassic Period.The brittle deformation experienced early pression period and late tension period.By comparing the tectonic-magmatic events with the regional tectonic evolusion, we propose that the coupling of three magmatic-hydrothermal events affected by regional extension contributed to mineralization of Yangshan gold deposit.

Key words: Yangshan gold deposit, tectonic evolution, magmatic-hydrothermal event, gold mineralization, Gansu