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与研究历史较长的K-Ar、U-Th-Pb和R_b-S_r等同位素年代法相比,Sm-Nd法还是一门新兴的方法,仅有4—5年的研究历史。 Sm-Nd法的根据是天然放射性同位素Sm~(147)经过一次α衰变〔T_(1/2)=1.060±0.008×10~(11)年(1σ)〕以后生成稳定的Nd~(143)。于是应用这一对母-子体同位素则可进行岩石和矿物的年龄测定。此外,还可用Nd~(143)作为地质“示踪剂”来研究岩石成因,成岩物质来源,以及探讨天体及地壳与上地幔的演化。
The Sm-Nd method is still an emerging method compared with other dating methods such as K-Ar, U-Th-Pb and R_b-S_r, which have a long history of research, and only have a history of 4-5 years. The Sm-Nd method is based on the formation of a stable Nd ~ (143) after the natural radioisotope Sm ~ (147) undergoes an alpha decay [T 1/2 = 1.060 ± 0.008 × 10-11 years] . The application of this pair of mother-daughter isotopes allows for the age determination of rocks and minerals. In addition, Nd ~ (143) can also be used as a geological “tracer” to study the origin of rocks, the source of diagenetic material, and the evolution of celestial bodies and the crust and the upper mantle.