Fluid mixing as the mechanism of formation of the Dajing Cu-Sn-Ag-Pb-Zn ore deposit,Inner Mongolia ——Fluid inclusion and stable isotope evidence  

作　　者：刘伟 李新俊 谭骏 

机构地区：[1]Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences

出　　处：《Science China Earth Sciences》2003年第7期652-663,共12页中国科学（地球科学英文版）

基　　金：This work was supported by the Chinese Academy of Sciences(Grant Nos.KZCX1-07-04 and IGG CX2000-02).

摘　　要：Dajing Cu-Sn-Ag-Pb-Zn ore deposit, in the Inner Mongolia Autonomous Region of China, is a fissure-filling hydrothermal ore deposit. The d D values of quartz-hosted inclusion water are centered at -100 — -130. The d 34S values of sulfide ore minerals and d 13C values of carbonate gangue minerals vary from 0.3 to 2.6 and from -2.9 to -7.0, respectively. Integrated isotopic data point to two major contributions to the mineralizing fluid that include a dominant meteoric-derived groundwater, and sulfur and carbon species from hypogene magma. Linear trends are exhibited on the gaseous H2O versus CO2 plot, and plots of CO, N2, CH4, and C2H6. It is shown by quantitative simulation that magma degassing cannot explain the linear trends. Hence, these linear trends are interpreted in terms of mixing of CO2-rich magmatic fluid with meteoric-derived groundwater. The groundwater circulated in Paleozoic sedimentary rocks and absorbed CO, N2, CH4, C2H6 and radiogenic Ar from organic matter. Cooling effects resulting from mixing have caused the precipitation of ore minerals.Dajing Cu-Sn-Ag-Pb-Zn ore deposit, in the Inner Mongolia Autonomous Region of China, is a fissure-filling hydrothermal ore deposit. The d D values of quartz-hosted inclusion water are centered at -100 — -130. The d 34S values of sulfide ore minerals and d 13C values of carbonate gangue minerals vary from 0.3 to 2.6 and from -2.9 to -7.0, respectively. Integrated isotopic data point to two major contributions to the mineralizing fluid that include a dominant meteoric-derived groundwater, and sulfur and carbon species from hypogene magma. Linear trends are exhibited on the gaseous H2O versus CO2 plot, and plots of CO, N2, CH4, and C2H6. It is shown by quantitative simulation that magma degassing cannot explain the linear trends. Hence, these linear trends are interpreted in terms of mixing of CO2-rich magmatic fluid with meteoric-derived groundwater. The groundwater circulated in Paleozoic sedimentary rocks and absorbed CO, N2, CH4, C2H6 and radiogenic Ar from organic matter. Cooling effects resulting from mixing have caused the precipitation of ore minerals.

关 键 词：FLUID mixing  FLUID inclusion  quadrupole mass spectrometer  stable isotope  DAJING ore deposit. 

分 类 号：P611[天文地球—矿床学]