摘要
我们利用显微热台、冷台、少量化学分析、岩石薄片镜下观察等手段,研究了玉龙斑岩铜(钼)矿床流体包裹体的类型、大小、气液比、均一温度、压力、含盐度、子矿物、成分和复苏沸腾等,从而为阐明该矿床成矿流体的性质、成矿物理化学条件、蚀变和矿化作用以及成矿机制提供了有意义的材料。
By means of micro-heat stage,freeze stage,trace chemical analysis and polarizing microscope,the authors have studied the type,frequency,size,temperature,pressure,salinity daughter minerals,ratio of gas to liquid,revivable boiling and composition of fluid inclusions in the Yulong porphyry copper(molybdenum)deposit.From the data acquired,a series of very interesting problems such as the character of thermal fluid,physico-chemical condition,alteration,mineralization and its possible mechanism have been suggested.Various minerals of the Yulong porphyry copper(molybdenum)deposit,are rich in fluid inclusions.Inclusions of different types(gaseous,liquid and poly-phase)are usually associated in the same sample or even the same mineral.In the monzouitic granite porphyry showing,biotite-potash feldspar alteration the inclusions are dominantly gaseous and poly-phase;while in the porphyry with quartz-potash feldspar and quartz-sericitization alteration mainly poly phase and a little gaseow and liquid ones.In the altered argillic monzonitie porphyry and the altered propylitic country rock liquid inclusions predominate while gaseous and poly-phase ones are of minor amount.Gaseous ones appear,however,to be more dominant in the countryrock overlying the intrusive body.The homogenous temperatures of the inclusions range from 600℃to 180℃;the deposition temperatures of Cu-Mo sulphides range from 420°to 250℃.From the center of the porphyry body to the wall-rocks the temperature of mineralization decreases gradually.The salinity of the fluid inclusions ranges from 6 to 56 wt.%,but the highly-saline poly-phase inclusions are concentrated only in the region of economic mineralization.The Cu-Mo sulphides were deposited under the highly saline fluidity condition.The pressures at the moment of homogenization is calculated to range from 100 to 1800 atm.The revivable boiling of the fluids is manifested at the top of the porphyry body by an intimate coexistence of gaseous and polyphase inclusions.The fluid in the inclusions belongs to the NaCl-KCl(CaCl_(2),MgCl_(2))-CaSO_(4)-H_(2)O type.As indicated by our analyses the thermal fluids of mineralization were rich in halogen,alkaline metals,but poor in base metals,sulphur,phosphorus and so on,with very high temperature(600℃)during the initial stage.Such thermal fluids could easily have extracted the metals out from the country rocks around the tunnel through which they rose.When they rose up and gathered into the top of the porphyry intrusive and its neighbouring wall-rocks,both alkali and hydrogen metasomatism would take place inevitably with the ensued decrease in temperature,thus giving rise to the deposition of metal sulphides.
作者
李荫清
芮宗瑶
程莱仙
Li Yinqing;Rui Zongyao;Cheng Laixian(Institute of Mineral Deposits,Chinese Academy of Geological Sciences)
出处
《地质学报》
1981年第3期216-231,共16页
Acta Geologica Sinica
