| The Yuhai porphyry Cu deposit is located in the southern part of the Dananhu-Tousuquan island arc belt of Eastern Tianshan orogenic belt.Based on the observations and the study,The veins in the yuhai can be divided into three stages: Quartz-chalcopyrite-pyrite?I?,Quartz-pyrite veins?II?and Late stage?III?,mineralization occurs primarily in the first phase.Based on the study of the fluid inclusions in quartz veins,we have found that four types of fluid inclusion are present in this deposit: gas-rich,liquid-rich,CO2-bearing three-phase and liquid phase inclusions.According to the temperatures: In the Quartz-chalcopyrite-pyrite?I?,we can find gas-rich,liquid-rich,CO2-bearing three-phase fluid inclusions,homogeneous temperatures of fluid inclusions vary from 269 °C to 388 °C.Salinities range from 2.6 to 10 wt.% NaCl eqv..Densities range from 0.64 g.cm3 to 0.87 g.cm3;In the Quartz-pyrite veins?II?,we can find gas-rich and liquid-rich,homogenization temperatures of fluid inclusions vary from 196 °C to 340 °C,salinities range from 0.2 to 8.3 wt.% NaCl eqv..Densities of the fluid range from 0.67 g.cm3 to 0.92 g.cm3;In the Late stage?III?,we can find liquid-rich,homogeneous temperatures of fluid inclusions vary from 154 °C to 217 °C.Salinities range from 0.4 to 6.7 wt.% NaCl eqv..Densities range from 0.85 g.cm3 to 0.96 g.cm3.The entire evolving trend of the hydrothermal fluids of the Yuhai porphyry Cu deposit is: early-stage high temperature,medium to low salinity,CO2-rich magmatic fluids transforming to the meteoric fluids of low-temperature,low-salinity CO2-poor at the late-stage.The ?34S values of the pyrite and chalcopyrite range from-0.6‰ to +0.2‰,with an average of-2.7‰,suggesting that the ore-forming materials mainlygenerated from deep magma. |
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