锡在流体和花岗质硅酸盐熔体间分配行为的实验研究  

Experimental Study on the Tin Partition Between Granitic Silicate Melt and Coexisted Aqueous Fluid

作　　者：胡晓燕[1] 尚林波[1] 毕献武[1] 胡瑞忠[1] 樊文苓[1] 陈佑纬[1] 

机构地区：[1]中国科学院地球化学研究所矿床地球化学国家重点实验室

出　　处：《矿物岩石地球化学通报》2007年第4期359-365,共7页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金资助项目(40373020;40503007);中国科学院西部之光项目;中国科学院知识创新工程重要方向项目(KZCX3-SW-125)

摘　　要：锡的成矿与花岗岩有着密切关系。为深入了解不同的岩浆组成及流体变化对锡分配行为的影响,以不同化学组成的凝胶和不同的流体分别作为初始固液相,进行了锡在流体与花岗质熔体间的分配行为实验研究。实验温度为850℃,压力为100 MPa。结果显示,当液相为0.1 mol/L的HCl时,熔体组成的变化对锡的分配行为有着明显的影响,锡在流熔体间的分配系数DSn随熔体中碱质(Na2O+K2O)含量、钠钾(Na/K)和碱铝(AlK/Al)摩尔比的增加而减小;在固相(富钾过碱质熔体)不变的前提下,DSn随流体相中HCl浓度的增加而增大,而流体相中HF及K+、Na+浓度的改变对DSn影响不大;流体Cl-浓度和酸度升高有利于锡分配进入流体相。The tin mineralization is one typical kind of mineralization closely associated with granite. In order to deeply understand the influence on the tin partition in various granitic silicate melts and coexisted aqueous fluids caused by the variation of their compositions, an experimental study on the tin partition in various gels （representative of granitic silicate melts） and various aqueous fluids has been carried out at the temperature of 850℃ and pressure of 0.1 MPa. The experimental results show that the tin partition coefficients Dso（Dsn=Cv/Cm, where Cv and Cm are the concentrations of Sn in the aqueous fluid and the melt, respectively） are affected obviously by the variation of the melt compositions when the liquid contains 0.1 mol/L HCl, as the Dso values is decreased due to the increase of the alkali （Na2O＋K2O） concentrations and the Na/K and alkali/A1 mole ratios of the melts respectively. Dsn values are positively increased with the HCl concentrations in the liquid phase are increased when the solid phase （K-rich ultra-alkaline melts） remains unchanged. However, the variation of HF and K^＋ , Na^＋ concentrations of the liquid phase has little influence on the Dsn values. With the increase of Cl^- concentrations and the decrease of pH values of the fluids, the tin is preferential partitioned into the fluid phase. These indicate that both pH values and chlorine concentrations of the fluids are important factors governing the distribution behavior of tin, but the partition coefficient for tin is almost independent to K^＋ or Na^＋ and fluorine concentrations in the fluid.

关 键 词：锡 流体 硅酸盐熔体 分配行为 实验研究 

分 类 号：P588.121[天文地球—岩石学]