首页|Late Jurassic epithermal mineralization of Shitouban Au deposit, Dehua-Youxi area, southeast China: Quartz Rb[sbnd]Sr dating, fluid inclusions, and H-O-S-Pb-Sr isotope analyses
Late Jurassic epithermal mineralization of Shitouban Au deposit, Dehua-Youxi area, southeast China: Quartz Rb[sbnd]Sr dating, fluid inclusions, and H-O-S-Pb-Sr isotope analyses
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NSTL
Elsevier
? 2022 Elsevier B.V.Shitouban Au deposit is a vein-type deposit, which located in the Dehua-Youxi area (Fujian Province, southeast China) and hosted by late Jurassic volcanic-sedimentary rocks. In this study, a detailed investigation on fluid inclusions, multiple isotopic compositions (H-O-S-Pb-Sr) and Rb[sbnd]Sr isotope dating of quartz have been carried out in an attempt to constrain the ore-forming processes and ore genesis. The deposit shares a characteristic of low-sulfidation epithermal Au deposit, such as low-temperature (peak Th 160–180 °C, average 168 °C) and low-salinity (2-3 wt% NaCl equiv., average 2.47). The hydrogen and calculated oxygen isotope values for fluids are ?64 to ?54‰ (average ? 60‰) and - 0.95 to 0.76‰ (average 0.15‰) respectively, indicating that the ore-forming fluid was a mixture of dominant meteroric water and subsidiary magmatic fluid. Pyrite from the deposit shows a δ34S range from - 4.5 to - 1.2‰ (average ?2.4‰), indicating a magmatic sulfur. The lead isotope ratios of pyrite, 206Pb/204Pb (18.399–18.494), 207Pb/204Pb (15.695–15.841), 208Pb/204Pb (38.842–39.297), are more radiogenic than the Jurassic magmatic rocks in the area, indicating a mixing metal source of magmatic and basement rocks. Based on the Rb[sbnd]Sr isotopic isochron age of Au-bearing quartz, the metallogenic epoch of Shitouban Au deposit is 157 ± 1 Ma, and consistent with the Jurassic volcanism in the Dehua-Youxi area. It is proposed that the primary hydrothermal fluids may have exsolved from the late Jurassic magma chamber and subsequently ascent into the shallower crust level near paleosurface to mix with meteoric water, which cause precipitation of Au and sulfides in the epithermal environment due to a decrease in metal solubility triggered by fluid boiling, cooling, and mixing.
Epithermal Au mineralizationLate JurassicLow-sulfidationShitoubanSoutheast China
Xiao F.、Fan F.-P.、Xing G.-F.、Jiang S.-Y.
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School of Earth Sciences and Engineering Nanjing University
Nanjing Center China Geological Survey
State Key Laboratory of Geological Processes and Mineral Resources School of Earth Resources Collaborative Innovation Center for Exploration of Strategic Mineral Resources China University of Geosciences
NSTL
Elsevier
