矿物流体包裹体中稀有气体的保存能力初探

查明流体包裹体中稀有气体的保存能力,对于判断其初始组分特征是否因后生作用而发生改变具有重要意义.文章以Ar为例,从扩散动力学角度对稀有气体地球化学研究中常用的矿物中流体包裹体稀有气体的保存能力进行了定量分析和系统比较,计算了Ar在这些矿物中的封闭温度以及不同温度条件下的保存时间,得出相同条件下各矿物对Ar、He等保存能...

A preliminary study of the retention of noble gases in fluid inclusions of different minerals

Studies of the retention of noble gases in fluid inclusions from various hydrothermal minerals are necessary for tracing the source of ore-forming fluid by using noble gas isotopic geochemistry. Mainly with Ar as an example, the retention of noble gases in several minerals commonly used to study fluid inclusion geochemistry was quantitatively evaluated and systematically compared with each other in this paper in terms of diffusion dynamics. In addition, closure temperature and preservation time of noble gases in these minerals were also calculated. The result reveals that, under the same conditions, the component characteristics of Ar, He and other noble gases can be preserved in these minerals in order of barite (=celestite) > chalcopyrite > pyrite > galena > sylvite > sphalerite > fluorite > wolframite > scheelite > beryl > calcite > quartz. It is also indicated that the closure temperature of Ar in quartz is more sensitive to the change of grain size than that of other minerals and will increase rapidly with the radius of the crystal, but the diffusivity is insensitive to the change of temperature. On such a basis, the authors present a theoretical scale for accurate assessment of variations of noble gas components resulting from post-entrapment processes.