硒同位素地球化学研究进展与应用  

Application and progress in selenium stable isotope geochemistry

作　　者：朱建明[1,2] 谭德灿 王静[2] 曾理[2] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [2]中国科学院地球化学研究所环境地球化学国家重点实验室,贵州贵阳550002 [3]中国科学院大学,北京100049

出　　处：《地学前缘》2015年第5期102-114,共13页Earth Science Frontiers

基　　金：国家重点基础研究发展计划"973"项目(2014CB238903);国家自然科学基金项目(41273029;41021062)

摘　　要：多接收杯电感耦合等离子体质谱仪（MC-ICPMS）与氢化物发生系统（HG）在线联机自动测样的实现，极大提高了硒（se）同位素的分析精度和效率，推进了Se同位素地球化学的发展。本文综述了Se稳定同位素研究的最新进展及其在地质与环境中的应用。自然界中Se同位素（δ82／76Se）的变化范围可达-12．40‰～11．37‰。其同位素分馏主要取决于硒氧阴离子团的氧化还原反应，而地表水体与氧化海洋环境中的硒同位素分馏极可能与铁氧化物吸附、浮游生物的吸收有关，均可引起约1‰的分馏，且在吸附／吸收相中均倾向富集se的轻同位素。黑色岩系中Se同位素尚未明确对古海洋还原环境的指示，但近地表中Se同位素存在的强烈分馏，指示大陆地表发生的氧化还原事件极可能导致Se同位素的明显分馏，使河流相倾向富集Se的重同位素。因此，Se同位素有可能成为了解局域至区域沉积环境的氧化还原条件以及古海洋化学演化的潜在指标。随着其分馏机制的进一步阐明，Se同位素有可能在地球、环境与生命科学中得到更为广泛的应用。The development of multi-collector inductively coupled plasma mass spectrometry （MC-ICPMS） with hydride generator has been realized the on-line automatic measurement of Se isotopes in samples, which greatly improves the analytical accuracy and efficiency, promoting the advances of Se isotope geochemistry. In this paper, we review the recent progress of the systematics of Se stable isotope and its applications in geological and environmental sciences. The natural range of δ82/76 Se is from --12. 40‰ to 11.37‰ The fractionation of Se isotopes depends mainly on the redox reactions of Se oxyanions, while in the surface water and oxidizing marine environment; it is very likely to be constrained by iron oxides＇ adsorption and assimilations by plankton, which can cause the fractionation of approximately 1‰, and the light Se isotopes tend to be enriched in the adsorption/absorption phases. To date, Se isotopes in black shales have not clearly become a proxy of indicating reduction environment of paleo-ocean. However, strong Se isotopic fractionation was observed in near surface, indicating redox reactions in earth surface are dominant factors leading to the obvious fractionation of Se isotopes, in which heavier isotopes are preferentially enriched in river water. Therefore, Se isotopes may become a potential indicator of understanding the oxidation and reduction of local or regional depositional environment, and the evolution of paleo-ocean chemistry. As the mechanism of Se isotope fraetionation is further elucidated, Se isotopes have the potential to be widely applied to more areas in earth, environment and life sciences.

关 键 词：Se同位素 分析方法 分馏机理 地质与环境应用 多接受杯电感耦合等离子体质谱仪 

分 类 号：P597.2[天文地球—地球化学]