LA-MC-ICP-MS锆石Hf同位素的分析方法及地质应用

Laser ablation-MC-ICP-MS technique for Hf isotope microanalysis of zircon and its geological applications.

本研究利用Thermo Finngan Neptune型多接收等离子质谱和Newwave UP213激光剥蚀系统对两个国际锆石标准和一个实验室锆石标准进行了系统的测定。测得的TEMORA、GJ1和FM02锆石标准的^(176)Hf/^(177)Hf比值分别为:0.282700±64 (2SD,N=22),0.282008±25(2SD,N=26)和0.282967±44(2SD,N=27),该结果在误差范围内与文献报道值完全一致。采用不同的剥蚀直径对FM02锆石标准进行了对比测定,结果在误差范围内是一致的。从分析结果来看,GJ1和FM02的Hf同位素比值变化范围较小,是Hf同位素LA-MC-ICP-MS测试的理想标准锆石。文中还对四个不同地区的锆石Hf同位素进行了测定,结合前人研究,对其成因和物质来源进行了初步探讨。

Two international zircon standards and one laboratory zircon standard were systematically measured using a Thermo Finngan Neptune MC-ICP-MS system and a New Wave UP213nm laser ablation system. The obtained Hf-176/Hf-177 ratios are 0.282700 +/- 64 (2SD, N = 22) for TEMORA, 0.282008 +/- 25 (2SD, N = 26) for GJ1 and 0.282967 +/- 44 (2SD, N = 27) for FM02. The results are in good agreement with the previously reported data within errors. Comparative measurements of the FM02 zircon standard using different ablation diameter show that the results are consistent within errors. Zircons GJ1 and FM02 show narrower variations in Hf-176/Hf-177 ratios than those of zircons TEMORA and thus are ideal standards for the Hf isotope analysis. The origin and material source of zircons from four different areas are also discussed based on the analysis of the Hf isotope compositions of zircons.