新疆西天山托克赛铅锌矿床叠加成矿作用--来自流体包裹体及H-O同位素的制约

Superimposed Mineralization of the Tuokesai Pb-Zn Deposit in Western Tianshan,Xinjiang--Constraints from Fluid Inclusions and H-O Isotopes

托克赛中型铅锌矿位于西天山成矿带赛里木微地块。矿床成矿过程划分为喷流沉积、变质改造和岩浆热液3个时期。喷流沉积期具典型SEDEX矿床特征,“岩控性”与“层控性”明显,成矿流体以海水为主;变质改造期发育富液相包裹体,包裹体均一温度210℃~271℃,w(NaCl_(eq))为12.7%~13.6%,成矿流体主要来源于变质热液;岩浆热液期发育富气相、富液相和含子矿物包裹体,包裹体均一温度190℃~341℃、w(NaCl_(eq))为4.8%~40.8%,成矿流体主要为岩浆水与大气水的混合。矿床的矿源层形成于古元古代的海底喷流沉积环境,后期经历了变质改造和岩浆热液叠加成矿作用。

The medium-sized Tuokesai Pb-Zn deposit is located in the Sailimu micro-block,Western Tianshan metallogenic belt.Three metallogenic periods are identified in the Tuokesai deposit:exhalaive sedimentation,metamorphism reformation and magmatic hydrothermal period.The exhalaive sedimentation period has the characteristics of a typical SEDEX deposit,has obvious"rock control"and"stratification control",the ore-forming fluids are mainly derived from seawater;the metamorphic transformation period,develops liquid-rich aqueous,homogenization temperature is 210℃~271℃,the salinity is 12.7%~13.6%.The ore-forming fluid is mainly derived from metamorphic hydrothermal fluid;vapor-rich aqueous,liquid-rich aqueous and halite-bearing are developed in quartz during the superposition of magmatic hydrothermalism period.Homogenization temperature for fluid inclusions is 190°C~341°C and yield salinities of 4.8%~40.8%.The ore-forming fluid mainly comes from the mixing of magmatic water and atmospheric water.The source layer was formed in the Paleoproterozoic submarine exhalaive sedimentation environment,and overlying by later metamorphic transformation and superimposed magmatic hydrothermal mineralization.