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Re-Os体系是一种重要的放射性同位素体系,187Re通过β衰变成187Os,因此可以利用Re-Os体系定年,它是目前厘定金属矿床成矿时代的最直接手段。Re和Os都是高亲铁性元素,集中分布在地核内,地幔及地壳丰度极低,对于常见地质样品,要想获得准确的Re、Os含量必须使用同位素稀释法进行测定。同位素稀释法是一种高精度的化学分析方法,向样品中加入已知质量和同位素组成的稀释剂,待样品溶解、同位素交换平衡后,测定样品+稀释剂的同位素组成变化,以此计算样品中待测
The Re-Os system is an important radioisotope system. 187Re decays into βOs by β, so it can be dated by Re-Os system. It is the most direct method to determine the metallogenic age of metallogenic deposits. Both Re and Os are high-pro-iron elements, which are concentrated in the core and have very low mantle and crustal abundance. For common geological samples, the isotope dilution method must be used to determine the exact Os content. Isotope dilution method is a high-precision chemical analysis method, to the sample by adding a known mass and isotopic composition of the diluent, until the sample is dissolved, isotope exchange equilibrium, the sample + diluent isotope composition changes measured as a sample In the test