Stable isotope geochemistry and ore genesis of Caixiashan Pb-Zn deposit at eastern Middle Tianshan, Xinjiang

Caixiashan is the largest Pb-Zn deposit in the Kawabulake—Xinxinxia Middle Tianshan massif.Ore bodies are hosted in the first member of early Neoproterozoic Kawabulake group,which comprises clastic rocks and carbonatites.The deposit is well controlled by the near EW structures with stratoid and lenticular ore bodies dipping 65° 80° to the south.The ore bodies are distributed in the faults and mylonites.C—O—H isotopes indicate that the fluid and volatile are mainly from magmatic source,then react with carbonatites and dissolve the carbonates,and at last form new calcite and quartz.Sulfur isotope displays that sulfur mainly originate from sulfate-reduction of sea water.Lead isotope reveals that it is mainly provided by magmatic fluid and contaminated by the wall-rock lead.The ore-forming mechanism describes that magmatic fluid carries considerable volatile matter and metals;when it travels trough fault-induced channel and encounters with the carbonate-rich wall rock,the metals combine with the sulfur from the wall rock and precipitate.Based on the characteristics of ore deposit geology and isotope geochemistry.Caixiashan Pb-Zn deposit is a structure-controlled magmatic hydrothermal deposit.