Fluid Inclusions and Stable Isotope Geochemistry of Gold Mineralization Associated with Fine-Grained Granite: A Case Study of the Xiawolong Gold Deposit, Jiaodong Peninsula, China

The Xiawolong gold deposit, located in the Muping–Rushan metallogenic belt (eastern Jiaodong Peninsula), is a newly discovered deposit that developed late Early Cretaceous as fine-grained granite. Gold mineralization, which mainly occurs middle of fresh granite dikes, consists stockwork-style and disseminated ores. They are characterized by middle-high-temperature mineral assemblages, such molybdenite magnetite, associated with gold-bearing pyrite. Four types primary fluid inclusions, contained within quartz grains from granitic ores, were identified based on microthermometry Raman spectroscopy. type 1 aqueous inclusions middle-high temperature (201 to 480 °C) middle-low salinity 0.18 17.00 wt.% NaCl equiv.; 2 H2O–CO2 show temperatures (218 385 °C), salinities (1.23 13.26 equiv. NaCl), variable XCO2 (0.031 0.044); 3 daughter mineral-bearing high (416 446 relatively constant (28.59 32.87 equiv.); 4 CO2 possess bulk density 0.405 0.758 g/cm3 (0.952 0.990) (according decreasing abundance inclusions). δ18Owater range between 3.4 5.9‰, δD −97.1 −77.4‰, indicates ore-forming process magmatic water origin. δ34S values narrow 4.5 9.3‰, indicating source Mesozoic Kunyushan granitoids. Pb isotopic compositions pyrite granitoids main lead for pyrites. Types 1, 2, coexist same view field grain, suggested occur result immiscibility because boiling single homogeneous NaCl-CaCl2-KCl-CO2-H2O system. immiscibility, rather mixing wall-rock sulfidation, mechanism precipitation deposit. Compared both “Linglong-type” “Jiaojia-type” deposits Peninsula terms geological–petrographic evidence all available geochemical data, it can be concluded hydrothermal origin, having genetic relation