银同位素在行星和地球科学中的研究进展  

Progress of Silver Isotopes Studies in Planetary and Earth Sciences

作　　者：朱原峰 董戈 刘茜 盛雪芬 魏海珍[1,3] Zhu Yuanfeng;Dong Ge;Liu Xi;Sheng Xuefen;Wei Haizhen(State Key Laboratory for Mineral Deposits Research,School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China;Key Laboratory of Surficial Geochemistry,Ministry of Education,School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China;Center for Excellence in Comparative Planetology,Chinese Academy of Sciences,Hefei 230026,China)

机构地区：[1]南京大学地球科学与工程学院,内生金属矿床成矿机制研究国家重点实验室,江苏南京210023 [2]南京大学地球科学与工程学院表生地球化学教育部重点实验室,江苏南京210023 [3]中国科学院比较行星学卓越创新中心,安徽合肥230026

出　　处：《地球科学》2021年第12期4390-4404,共15页Earth Science

基　　金：国家自然科学基金项目(Nos 41973005,41673001);国家国防科技工业局民用航天技术预先研究项目(No.D020205)。

摘　　要：系统梳理了放射性Pd-Ag体系银同位素在行星科学中的发展概况以及稳定银同位素在环境科学示踪和金银矿床中的研究进展.在太阳星云以及行星核的形成过程中,由于^(107)Ag可由^(107)Pd经β衰变产生,而挥发性元素的耗散又会造成早期Pd/Ag的分异,使得Pd-Ag同位素体系可以用于早期太阳系的活动历史研究,例如定义行星核的形成、限定行星形成时代.在稳定银同位素体系中,已探明银同位素组成(δ^(109)Ag)变化范围为-1.0‰~+2.3‰.稳定银同位素组成在不同环境的样品中具有类似于"指纹"特性,可用于确定污染物来源,追溯污染物环境过程,还原真实的环境系统.在金银矿床研究中,具有显著变化的银同位素组成使其在贵金属矿床的形成及演化机制上具有直接的应用意义.目前银同位素在解答行星科学及地球科学等诸多领域问题上仍存在一些尚未解决的难题,例如放射性Pd-Ag体系中太阳系初期^(107)Pd/^(108)Pd比值的精确限定、环境及矿床中银迁移沉积的物理化学过程的复杂耦合同位素分馏机制的确定等.The progresses of the radioactive Pd-Ag system in planetary sciences and the stable silver isotope in environmental sciences and ore-deposits are systematically reviewed in this paper.In the formation of solar nebula and planetary nucleus,^(107)Ag can be produced by ^(107)Pd through β decay,and the dissipation of volatile elements will cause the early Pd/Ag differentiation,which makes the Pd-Ag system applicable to investigate various activities of the early solar system,such as defining the formation of planetary nucleus and the age of planetary formation.In the stable silver isotope system,it has been proved that the wide variation range of δ^(109)Ag is-1.0‰to+2.3‰ in terrestrial materials.Stable silver isotope has characteristics similar to“fingerprint”in environmental materials,which makes it possible to effectively determine pollutants sources and to track migration paths of pollutants.Much wider variations of δ^(109)Ag in metallic ore-deposits have been observed,showing a great potential of silver isotope in studying the genesis and evolution mode of Au-Ag deposits.However,there are still many concerns remained to be resolved,such as the precise definition of ^(107)Pd/^(108)Pd ratio in the early solar system of radioactive Pd-Ag system,and the quantification of silver isotope fractionation in physiochemical processes(e.g.,boiling/phase separation,multistage ore paragenesis,precipitation,redox,adsorption and remobilization etc.)involved in silver migration and deposition in environmental and ore-forming processes.

关 键 词：银同位素 放射性Pd-Ag体系 环境污染物示踪 金银矿床 地球化学 

分 类 号：P581[天文地球—岩石学]