NaCl-X-H_2O三元体系25℃等温蒸发石盐流体包裹体均一温度实验研究

Experimental studies of homogenization temperature of fluid inclusions of halite by isothermal evaporation at 25℃ involving NaCl-X-H_2O (X=KCl,MgCl_2, CaCl_2, Na_2SO_4) system

复杂卤水组分对于石盐流体包裹体均一温度的影响尚不明确,文章基于NaCl-X-H_2O(X=KCl, MgCl_2,CaCl_2, Na_2SO_4)三元卤水体系,尝试探讨K^+、Mg^(2+)、Ca^(2+)、SO_4^(2-)对石盐流体包裹体均一温度测试结果的影响。不同卤水体系最大均一温度分析结果表明,K^+、Mg^(2+)、Ca^(2+)的存在总体上会导致石盐流体包裹体均一温度偏大,SO_4^(2-)的存在对均一温度的影响很小。以NaCl-H_2O体系为参照,NaCl-Na_2SO_4-H_2O体系平均均一温度较之要低,而NaCl-KCl-H_2O、NaCl-MgCl_2-H_2O和NaCl-CaCl_2-H_2O体系与其相反。NaCl-KCl-H_2O体系中的KCl浓度与平均均一温度呈现负相关关系,NaCl-MgCl_2-H_2O、NaCl-CaCl_2-H_2O、NaCl-Na_2SO_4-H_2O体系中的w(MgCl_2)、w(CaCl_2)和w(Na_2SO_4)与平均均一温度则呈现正相关关系。平均和最大均一温度分析结果都显示出复杂卤水体系中不同离子及其浓度对石盐流体包裹体均一温度会产生影响。本研究对于具有复杂化学组分卤水结晶析出石盐均一温度的研究具有重要的参考价值。

The influence of complex brine components on homogenization temperature of halite is unclear. Based on the ternary system of NaCl-X-H2O (X=KCl, MgCl2, CaCl2, Na2SO4), the authors attempted to discuss the effect of K^+, Mg^2+, Ca^2+, SO4^2- on the result of homogenization temperature (th) of halite fluid inclusions in this paper. An analysis of the Thmax in different brine systems shows that the existence of K^+, Mg^2+, Ca2^+ will generally lead to higher Thmax of halite fluid inclusions and the existence of SO4^2- has little influence on the Thmax. With the NaCl-H2O system as a reference, average Th of NaCl-Na2SO4-H2O system is lower than that of the NaCl-H2O system, while average th of NaCl-KCl-H2O, NaCl-MgCl2-H2O and NaCl-CaCl2-H2O are higher. In NaCl-KCl-H2O system, the relationship between the average Th and KCl concentration is negative. In NaCl-CaCl2-H2O, NaCl-Na2SO4-H2O and NaCl-MgCl2-H2O systems, the relationship between the averageth and the concentration of CaCl2, Na2SO4 and MgCl2 is positive, respectively. An analysis of the average and max th shows obviously that the complex brine system will exert influence on the Th of halite fluid inclusion. This study provides an important reference for the study of th of halite from brines with complicated chemical components during evaporation experiment.