高温地质过程镍同位素地球化学研究进展  

Research progresses on Ni isotope geochemistry during high-temperature geological processes

作　　者：段庆 陈列锰[1] 周生华 康健[1,2] DUAN Qing;CHEN Lie-meng;ZHOU Sheng-hua;KANG Jian(State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;UniversityofChineseAcademyof Sciences,Beijing100049,China)

机构地区：[1]中国科学院地球化学研究所,矿床地球化学国家重点实验室,贵阳550081 [2]中国科学院大学,北京100049

出　　处：《矿物岩石地球化学通报》2023年第4期914-930,共17页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金资助项目(41873026,42173020);中国科学院“西部之光”青年学者B类项目。

摘　　要：镍(Ni)具有独特的地球化学性质,其同位素在示踪早期地球的演化、大氧化事件、雪球地球、生物大灭绝、岩浆硫化物矿床成矿作用等方面显示出重要的潜力。本文系统综述了当前高温地质过程Ni同位素研究进展。已有研究初步查明了不同地质储库的Ni同位素变化范围。基于已发表的地幔橄榄岩、MORB、OIB和科马提岩的Ni同位素数据,估算全硅酸盐地球(Bulk Silicate Earth, BSE)的δ60NiBSE均值为0.10‰±0.18‰(2SD,n=179)。根据上述已有的Ni同位素数据,并结合实验岩石学和模拟计算,发现:(1)核幔分异过程不会产生可分辨的Ni同位素分馏;(2)地幔部分熔融和玄武质岩浆结晶分异过程不会产生显著的Ni同位素分馏;(3)地幔的Ni同位素组成明显不均一,可能与地幔交代和再循环物质加入相关;(4)岩浆硫化物熔离和分离结晶可能是导致Ni同位素分馏的重要过程。本文最后介绍了最新的Ni同位素研究实例,并尝试指出研究中存在的科学问题和探讨未来的发展前景。Ni is marked by unique geochemical featrues and its isotopes display a great potential for tracing the differentiation of the early Earth, the processes of the Great Oxidation Event, Snowball Earth, Mass Extinction, and the formation of magmatic sulfide ore deposits. Current research progresses on nickel isotope geochemistry during high-temperature geological processes are integrated in this study. The range of Ni isotopic variations in different types of igneous rocks has been obtained. On the basis of published data, the Ni isotopic composition of Bulk Silicate Earth(BSE), which is calculated from the average Ni isotope data of mantle peridotite, mid-ocean ridge basalts(MORBs), oceanic island basalts(OIBs), and komatiites, is estimated to be δ60Ni_(BSE)=0.10‰±0.18‰(2SD, n=179). Combining all Ni isotope data and experiment results, we suggest that:(1) no detectable Ni isotope fractionation occurs during core-mantle differentiation;(2) very limited Ni isotope fractionation occurs during partial melting of the mantle and/or silicate magmatic differentiation;(3) the heterogeneous Ni isotopic compositions of the mantle may be caused by mantle metasomatism and/or addition of recycled crustal materials;(4) large Ni isotope fractionation may occur during sulfide segregation and fractional crystallization. We describe the latest cases for Ni isotope studies and propose their related scientific issues and the future prospects at the end of this study.

关 键 词：镍同位素 非传统稳定同位素 同位素质量分馏 地球化学示踪 研究进展 

分 类 号：P595[天文地球—地球化学]