扫描电镜能谱与冷冻传输装置联用测试矿物中流体包裹体固液相成分的方法研究

摘要

研究流体包裹体中子矿物种类、化学成分及分布特征，对于确定热液成分和成矿物理化学条件、流体的演化规律和成矿机制等有非常重要的意义。但目前常用的各种测试研究方法存在测试目的物寻找困难、不透明子矿物难鉴定等局限性。本文采用冷冻传输装置首先将流体包裹体冷冻固定并打开，然后用扫描电镜、能谱仪测试矿物中流体包裹体中的子矿物和液相成分，该方法可解决扫描电镜下流体包裹体研究目标物不易寻找，打开流体包裹体后子矿物易散失和碎屑易混入的问题，可有效测试小颗粒（1~2μm）、不透明子矿物及不透明矿物中的流体包裹体固液相成分。用该方法实测山东邹平王家庄铜矿流体包裹体液相中Na﹢、K﹢、Cl-组分的质量分数分别为5.85％、3.60％、16.18％，计算的盐度为35.35％，并确定了其中不透明矿物子矿物为黄铜矿，证明了黄铜矿是从高盐度热液中晶出的结论。本方法为矿物中流体包裹体研究提供了一种新的测试手段。%Daughter mineral species,chemical compositions and distribution of daughter minerals in fluid inclusions can provide important constraints on the composition of hydrothermal fluids, physicochemical conditions of mineralization,the regularity of fluid evolution and ore-forming mechanisms. The traditional methods however, have many limitations such as finding target minerals and identifying opaque minerals. Described in this paper, fluid inclusions in minerals are frozen and then opened by Frozen Transmission Equipment( Cryotransfer ). The compositions of daughter minerals and liquid phases are determined by Scanning Electron Microscope( SEM)and Energy Disperse Spectroscope. This method solved the difficulty in finding target minerals by SEM. Daughter minerals cannot be lost after opening liquid inclusions,and cannot be mixed with debris. This method can effectively determine the compositions of small-sized(1 -2 μm)opaque daughter minerals and the solid-liquid phases of fluid inclusions in opaque minerals. Mass fractions of Na﹢, K﹢, Cl- in liquid inclusions of Wangjiazhuang copper deposit in Zouping of Shandong province are 5. 85%,3. 60% and 16. 18%,respectively, and the calculated salinity is 35. 35%. The opaque daughter minerals are identified to be chalcopyrite,which proves that chalcopyrite has crystallized from hydrothermal fluids with high salinity. This study provides a new determination method for fluid inclusion,and has great significance in analyzing the compositions of solid and liquid phases in fluid inclusions.