Abstract:

 On the basis of  the studies of sandstonetype and brecciolatype ores from Jinding superlarge leadzinc deposit in western Yunnan Province by systematically using petrography, electron microprobe, scanning electron microscopy and energy spectroscopy, and combined with the studies of isotopic geochemistry, we confirmed that the black opaque cements are the microproducts of speedily cooling of carbonatite melt which mixed heterogeneously with sulfides, and that they are the relic actual traces of mantle fluid contaminated with crustal fluid. The crustmantle transitive characteristics of noble gases in fluid inclusions from ore minerals suggested that during the transportation and mineralization processes of mantle fluid, the crustal fluid had made great contribution. The distribution style of Pb isotope provides a new understanding of the behaviors of Pb isotope in the crustmantle overprinted processes. We propose the main geochemical mechanism of the Jinding leadzinc deposit as follows: the mantle fluid derived from alkalirich porphyry transported along deep faults, metasomatically altered host rocks and was overprinted by crustal fluids.

Key words:  Jinding leadzinc deposit, petrographic characteristics, traces of mantle fluid, isotopic geochemistry, mantlecrust overprint