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用Rb-Sr法测定地质年龄,对地质样品中的锶往往要进行两种同位素分析:非稀释分析以测定~(87)Sr/~(86)Sr比值;稀释分析以测定样品中~(86)Sr的含量。随着稀释剂~(84)Sr丰度的提高,Wasserburg et al.(1964),Van schmus(1965),Wetherill与Bickford(1965)采用了以一代二的办法——用稀释分析既测定含量又测~(87)Sr/~(86)Sr比值。由于稀释剂中~(84)Sr高度富集,~(87)Sr/~(86)Sr受到的影响小,在当时的技术条件下,这些作者没有对一些数据处理进行讨论。但随着计算技术的应用,大大提高了测量精度,稀释剂对~(87)Sr/~(87)Sr的影响则必须加以考虑。
The Rb-Sr method is used to determine the geologic age. Two types of isotope analysis of strontium in geological samples are often performed: non-dilute analysis to determine the ratio of ~ (87) Sr / ~ (86) Sr; ) Sr content. Wasserburg et al. (1964), Van schmus (1965), Wetherill and Bickford (1965) used a second generation approach - using both diluted and analytically determined concentrations The ~ (87) Sr / ~ (86) Sr ratio was measured. Due to the high enrichment of ~ (84) Sr in the diluent, the effect of ~ (87) Sr / ~ (86) Sr was small, and under the technical conditions of the time, the authors did not discuss some data processing. However, with the application of computational technology, the measurement accuracy is greatly improved. The effect of diluent on 87 Sr / 87 Sr must be considered.