分散元素(Ge,Cd, Tl)稳定同位素研究

近年来,非传统稳定同位素地球化学得到了飞跃性的发展,其主要研究对象为海洋体系的演化。特别是氧化还原敏感元素(Se,Mo,Fe等)稳定同位素已经在古海洋环境的示踪研究中发挥重要的作用。相比分散元素(Ge,Cd,Tl)稳定同位素研究比较薄弱,但这些元素在海洋体系中有特殊的循环模式,这使得它们的同位素研究将可能存在很大地质潜力。海洋体系中它们的源汇简单,而且有机无机吸附过程都可能导致同位素分馏。Ge,Cd,Tl均属于挥发性元素,原始星云的形成过程可能存在较大的同位素分馏。我国南方大面积的低温成矿域,将为Ge,Cd,Tl稳定同位素的发展提供天然的平台。另外,Cd,Tl是环境污染的主要潜在元素,因此采用稳定同位素示踪还可能示踪表生环境中的污染来源。

A study of the stable isotopes of the disperse elements(Ge,Cd, Tl).

Recently, the non traditional stable isotopic geochemistry has achieved great advancement in the study of the evolution of paleo oceanic environment, in which the stable isotopes of redox sensitive elements (Se,Mo,Fe,etc.) have played an important role. In comparison, the use of stable isotopes of some disperse elements (Ge,Cd,Tl) in tracing the paleo oceanic environment was overlooked for years. But these elements have their own special recycling mechanism in the marine system, and thus, the trace of the stable isotopes of these elements may provide potential geological implications for the paleo oceanic environment. Their sources and sinks are simple in the marine system; moreover, both inorganic and organic adsorption could control their isotopic fractionations. On the other hand, Ge, Cd and Tl are easily evaporated at high temperature, and their major isotopic fractionation may have occurred during the formation of the primary nebula. There are large scale low temperature deposit field in South China, which would provide the best chance to the improvement of Ge,Cd,Tl stable isotopes. In addition, Cd and Tl are the potential toxic elements in the supergene environment; therefore, their isotopic composition could be used to trace the source of contamination.