MC-ICP-MS锂同位素溶液分析技术与应用

Lithium isotopic solution analysis using MC-ICP-MS and its applications

Li同位素是一种新兴的非传统稳定同位素示踪工具,在地质学、地球化学研究中具有广阔的应用前景。目前,Li同位素溶液分析技术主要采用热电离质谱仪(TIMS)和多接收电感耦合等离子质谱仪(MC-ICP-MS),与TIMS相比,MC-ICP-MS具有分析精度高、样品量少、测试速度快等诸多优点。本研究团队近年来建立了MC-ICP-MS高精度Li同位素分析方法,在天然样品、标准物质以及石英包裹体的Li同位素测定中都取得了良好结果。以此为依托,研究团队建立了适用于西藏本地岩石成因研究的Li同位素地质端元,并将Li同位素应用于青藏高原岩石圈结构及其隆升历史、川西碳酸岩型稀土矿床富集机制、四川呷村VMS型矿床成矿流体来源和四川甲基卡硬岩型Li矿床富集机理等方面。本文比较详细地综述了这些研究进展,旨在加深对Li同位素溶液分析技术的理解,展示其在地球化学研究中的良好应用前景。

Objectives: Lithium isotopes are one of the newly developed non-traditional stable isotope tracers. This isotopic system has been gaining increasing interest in fingerprinting geologic and geochemical processes. At present,lithium isotopic solution analyses mainly include thermal ionization mass spectrometry( TIMS) and multicollector inductively coupled plasma mass spectrometry( MC-ICP-MS). Compared with TIMS,MC-ICP-MS has many advantages,such as higher analysis accuracy and precision,less sample consumption,faster analysis speed and so on.Methods: In recent years,the research team have established high-precision measurement of lithium isotopes by MC-ICP-MS,which has achieved good results in the determination of lithium isotopes in natural samples,reference materials and quartz inclusions.Results: Based on these analytical methods,we have established the Li isotopic geological endmembers,which are applicable to the study of the origin of local rocks in Tibet. In addition,we have applied Li isotopes to the lithospheric structure and uplift history of the Qinghai—Tibet Plateau,the enrichment mechanism of carbonatitetype rare earth deposits in western Sichuan,the source of ore-forming fluids of Gacun volcanogenic massive sulfide(VMS) deposits in Sichuan and the enrichment mechanism of Jiajika hard-rock lithium deposits in Sichuan.Conclusions: In this paper,we present these representative applications in detail in order to deepen the understanding of lithium isotopic solution analysis and show its good application prospects in geochemical research.