The Zhenyuan gold orefield is located in the Ailaoshan gold belt, Sanjiang metallogenic region, China. The fluid inclusions （FIs） in mineralized quartz samples, collected from four deposits, i.e., Laowangzhai , Dong...The Zhenyuan gold orefield is located in the Ailaoshan gold belt, Sanjiang metallogenic region, China. The fluid inclusions （FIs） in mineralized quartz samples, collected from four deposits, i.e., Laowangzhai , Donggualin , Kudumu , and Daqiaoqing, in the orefield, were studied to reveal ore-forming process. Only aqueous-type and H20-NaCl-type FIs were observed in the samples. Two generations of FIs are identified due to the spatial occurrences of FIs in host minerals. The early generation is located in the internal zone of quartz crystal, and it has higher homogenization temperatures varying from 180 to 255 ℃ and salinities ranging from 8.7% to 11%; the late generation, often with beating bubbles under room temperature, is developed in the quartz margin, its homogenization temperatures is lower within 95 to 160 ℃. After elimination of the late generation of FIs, early generation FIs compositions were tested. Gaseous phases in the FIs were H20 and CO2, with low contents of N2, CH4, and C2H6, and the liquids mainly contains Na＋, K＋, Ca^＋,Mg^2＋, CI, and SO_4^2-. The reappraisal of the previously published hydrogen and oxygen isotope results suggested that the early generation of ore-forming fluid was mainly primary magma hydrothermal, while the late generation fluid contains large amounts of meteoric water. Thus, the result showed that Zhenyuan gold orefield may differ from typical orogenic deposits, which contains abundant CO2-dominated FIs. The two generations FIs developed as quartz grew displaying a continuous evolution of the ore-forming fluids.展开更多
基金supported by the National Key Basic Research Development Program (Nos. 2009CB421006,2009CB421008)the Century Training Program Foundation for the Talents of Humanities and Social Science by the State Education Commission (No. NCET-09-0710)the Program of Introducing Talents of Discipline to Universities of China (No. B07011)
文摘The Zhenyuan gold orefield is located in the Ailaoshan gold belt, Sanjiang metallogenic region, China. The fluid inclusions （FIs） in mineralized quartz samples, collected from four deposits, i.e., Laowangzhai , Donggualin , Kudumu , and Daqiaoqing, in the orefield, were studied to reveal ore-forming process. Only aqueous-type and H20-NaCl-type FIs were observed in the samples. Two generations of FIs are identified due to the spatial occurrences of FIs in host minerals. The early generation is located in the internal zone of quartz crystal, and it has higher homogenization temperatures varying from 180 to 255 ℃ and salinities ranging from 8.7% to 11%; the late generation, often with beating bubbles under room temperature, is developed in the quartz margin, its homogenization temperatures is lower within 95 to 160 ℃. After elimination of the late generation of FIs, early generation FIs compositions were tested. Gaseous phases in the FIs were H20 and CO2, with low contents of N2, CH4, and C2H6, and the liquids mainly contains Na＋, K＋, Ca^＋,Mg^2＋, CI, and SO_4^2-. The reappraisal of the previously published hydrogen and oxygen isotope results suggested that the early generation of ore-forming fluid was mainly primary magma hydrothermal, while the late generation fluid contains large amounts of meteoric water. Thus, the result showed that Zhenyuan gold orefield may differ from typical orogenic deposits, which contains abundant CO2-dominated FIs. The two generations FIs developed as quartz grew displaying a continuous evolution of the ore-forming fluids.
