| 其他摘要 | The Dulong skarn Sn-Zn pollymetallic deposit is one of the typical deposit in western nanling tin polymetallic metallogenic belt. Predecessors have carried out a large number of research work on ore deposit geology and geochemistry，but it is almost blank in terms of ore-forming fluid research. Due to the unique deposit geological characteristics, metallogenic element enrichment and complex mineralization of this deposit, At present, there are still considerable differences about the deposit genesis, thus it is difficult to establish unified metallogenic model. On the basis of detailed field investigation, we divide the ore deposits into different ore-forming stages, and have carried out detailed fluid inclusions, C, H, O, He and Ar isotopic geochemical research of all stages, to explore the nature, origin and evolution of ore-forming fluid. In combination with geological facts，we have constructed the metallogenic model of Dulong deposit. Through research, the following conclusions are reached: (1) The Dulong skarn Sn-Zn pollymetallic deposit can be divided into six mineralization stage, that is early skarn stage (calcium skarn and magnesia skarn), late skarn stage , oxide stage, early sulfide stage, late sulfide stage and carbonate stage; (2) The types of fluid inclusion in metallogenic stage and the granite can be divided into four categories: liquid-rich aqueous inclusions (Ⅰtype), gas-rich aqueous inclusions (Ⅱ type), pure gas phase inclusions (Ⅲ type) and melt inclusions (Ⅳ type). The quartz of Laojun Mountain granite has manyⅠtype inclusions and small amounts of Ⅳ type inclusions, and the salinity of Ⅰtype inclusions is moderate(7.2 ~ 9.5 wt % NaCl eq.), which show that in the process of magma crystallization, the single-phase supercritical fluid, riched in Sn, Cu, Zn, Pb, Ag metallic elements , exsolved from magma; The fluorite of the late skarn stage hostⅠtype inclusions, which have homogenization temperature between 376℃ ~ 419℃ (398℃on average), salinity range between 7.7 and 11.0 wt% NaCl eq.; The dolomite of Oxide stage develop a large number of Ⅰtype inclusions and Ⅲ type inclusions, containing a small amount of Ⅱ type inclusions.Ⅰ type inclusions homogenize as a liquid at temperatures range 323 to 405℃(358℃on average) , salinity values ranging from 6.74 to 10.36 wt.% NaCl eq. and the homogenization temperature of Ⅱ type inclusions range from 346 ℃ to 373 ℃, the salinity in 0.9 ~ 1.5% wt % NaCl eq. wt.%); The quartz and fluorite of early sulfide stage host the same types fluid inclusions as oxide stage.Ⅰtype inclusions homogenize at temperature between 245℃ and 362℃(304℃, the average), with salinity 6.9~14.1 wt% NaCl eq.,. Ⅱ type inclusions homogenize at temperature range from 295 to 317℃, with the salinity 0.9 ~ 1.7 wt% NaCl eq.; the types of fluid inclusions in quartz and fluorite of the late sulfide stage are consistent with those of oxide stage and early sulfide stage.Ⅰtype inclusions have homogenization temperature between 188 ℃ and 308 ℃ (246℃ on average), with the salinity 4.0 ~ 10.1 wt % NaCl eq.,. Ⅱ type inclusions have homogenization temperature between 241℃ and 268℃, with the salinity 0.7 ~ 1.7% wt % NaCl eq. The fluid inclusions of the oxide stage, early and late sulfide stage have different gas and liquid ratio, homogenization manner and roughly the same homogenization temperature, which indicates that fluid boiling happened. In addition, the calcite of carbonate stage hostⅠtype inclusions which have low temperature, range between 170 ℃ and 170 ℃ (204 ℃) on average, 4.2% ~ 11.7 wt % NaCl eq.,salinity; (3) The δ13CPDB value of dolomite in oxide stage is between 6.36 ‰ and 8.76 ‰. the late The δ13CPDB value of calcite in late sulfide stage is between 4.95 ‰ and 7.47 ‰,. The δ13CPDB value of calcite in carbonate stage is between 4.69 ‰ and 8.57‰, the study shows that the δ13CPDB value of dolomite and calcite is consistent with that of magmatic carbon and carbon originate from the magma；In addition, the flu |
修改评论