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Qingyunshan Cu-Au deposit: an intermediate-low temperature IS epithermal deposit. [Display omitted] • Qingyunshan Cu-Au deposit in Fujian province is a vein-type epithermal deposit. • H-O isotopes indicate a dominant meteoric water for ore fluids. • S-Pb isotopes indicate a major magmatic source for ore metals. • Pyrite Re-Os dating yielded an age of 158.1 ± 9.3 Ma. • Zircon U-Pb dating yielded an age of 162 ± 1.0 Ma for the Nanyuan Formation volcanic rock. The Qingyunshan Cu-Au deposit, located in the Dehua-Youxi area (Fujian Province, southeastern China), is a vein-type deposit that occurs along fractured zones in the Late Jurassic volcanic-sedimentary rocks and Early Silurian intrusions. Three mineral paragenetic stages are identified, including the pyrite-quartz veins (stage I), polymetallic sulfide-quartz-calcite veins (stage II), and calcite (±siderite)-chalcedony-comb quartz veins (stage III). The stage II is the main mineralization stage, dominated by pyrite, chalcopyrite, and galena as well as two generations of Fe-poor sphalerite with average Fe content of 0.84 wt% in the early sub-stage and 0.31 wt% in the late sub-stage. Fluid inclusion studies indicate that the stage I has a temperature of 220–240 °C and salinity of 3.00–3.50 wt% NaCleq., whereas the stage II has lower temperature (140–160 °C), but similarly low salinity (2.50–3.00 wt% NaCleq.), suggesting it is an intermediate-low temperature epithermal deposit. Hydrogen and oxygen isotope data indicate the fluids of stage I has a δD value of −72.5 to −69.5‰ and δ18O w value of −2.96 to −0.46‰, whereas the stage II fluids show similar or slightly higher δD value (−68.0 to −66.5‰), but significantly lower δ18O w value from −6.96 to −6.26‰, which suggest meteoric water predominated in the ore-forming fluid and shows an increasing trend from stage I to II. The δ34S values of sulfide minerals are between −3.7 and −2.3‰, consistent with a major magmatic sulfur source. The lead isotope data show a relatively narrow range with 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb values of 18.392–18.513, 15.642–15.758, and 38.497–39.043, respectively. These Pb-isotope data are similar to those of the Late Jurassic intrusions, but quite different from those of the surrounding rocks of Early Silurian quartz diorite. Pyrite from the ores yielded a Re-Os isochron age of 158.1 ± 9.3 Ma, which is similar to the zircon U-Pb age (162.0 ± 1.0 Ma) of the host dacite crystal tuff in the Nanyuan Formation. Therefore, we concluded that the Late Jurassic magmatic activity (ca. 160 Ma) has a genetic relation with formation of the Qingyunshan vein-type Cu-Au deposit, for which the ore metals were mainly derived from the magma, but ore-forming fluids evolved from a mixing of magmatic fluids and meteoric water with the later playing a major role in the main stage of ore formation. [ABSTRACT FROM AUTHOR]

• The ca. 154 ~ 154 Ma magmatic/hydrothermal episode is recognized. • The granitoids in Donghua exhibit characteristics of both A-type and I-type. • Favorable environment for mineralization in Donghua is distinguished. Located in the southern section of the Wuyi Mountain metallogenic belt, the Dehua-Youxi-Yongtai (DYY) ore district is one of the potential areas of gold deposits in the Fujian province, Southeast China. Gold mineralization is widely distributed in this district, including Qiucun, Shuangqishan, Ancun, and Dongyang gold deposits. However, the DYY ore district is still at a low degree of exploration and research. This paper focuses on the Donghua area in the northwest of the DYY ore district as its typical and integrated volcano-magma mechanism revealed in this study. Combined approaches including zircon SHRIMP U-Pb geochronology, Rb-Sr isochron dating and mineral chemistry of pyrite, and hyperspectral remote sensing are employed, aiming to identify the magmatism, alteration, geological setting, and metallogenic potential of the Donghua area. The zircon SHRIMP U-Pb ages of the granite porphyritic dykes in Donghua are 154.6 ± 1.1 Ma and 153.2 ± 1.2 Ma, respectively, indicating that the dykes were formed in the late Jurassic. The Rb-Sr geochronological age of hydrothermal/epithermal pyrite in Donghua is 153.7 ± 2.4 Ma, which is almost coeval with that of the granite porphyritic dykes within error, and consistent with the regional volcanic-magmatic activity and the metallogenic age of the regional metallogenic event. The granitic dykes in Donghua exhibit the characteristics of both A-type and I-type granitoids, thus indicating the presence of transitional geochemical characteristics. As a result of the subduction of the Pacific Plate towards the Eurasia, the ca. 154–153 Ma magmatic event in the Donghua area occurred at the beginning of large-scale delamination of the continental crust. The zoning distribution of the mineral alteration of chlorite, dickite, kaolinite, and gypsum, the interpretation of volcanic activity from the annular structure of hyperspectral remote sensing, and the inferred deep-seated intrusion emplacing from northwest to southeast are in agreement, thus displaying the volcano-magma-alteration mechanism developed in the Donghua area. The magmatism, dykes, faults, and Neoproterozoic metamorphic rock provide favorable advantages for the mineralization in Donghua, suggesting metallogenic potential. [ABSTRACT FROM AUTHOR]