风尘Sr同位素研究

Research on Sr Isotope in Dust 

中文关键词:  Sr同位素  风尘  粒度效应

英文关键词:Sr isotope  Dust  Grainsize effect

中文摘要:

      黄土和红粘土为风尘物质,其Sr同位素的研究较为深入,其它风尘物质还包括深海沉积物和冰芯中的粉尘物质,以及现代风尘物质,它们的Sr同位素亦有较多研究。Sr主要以分散形式存在于风尘物质含钙矿物中。风尘物质中碳酸盐矿物Sr同位素值低,硅酸盐矿物高。风尘物质Sr同位素示踪研究一般采用硅酸盐组分,但不同粒级组分Sr同位素组成不同,<2μm组分具有最高值,它影响全岩Sr同位素组成;采用固定粒级具有很好的示踪效果。利用碳酸盐Sr同位素进行风尘物源示踪,表明中国北方沙漠碳酸盐具有不同的Sr同位素组成,它受控于地质背景和化学风化程度。

英文摘要:

      :Loess and red clay, both components of dust, are formed by eolian action.Dust Sr isotope has been researched extensively nowadays, these researches focus not only on loess and red clay, but also dust in pelagic and ice core and modern dust. In dust, the element Sr is mainly contains in calcareous minerals.The Sr isotopic composition of carbonate in dust is low, and that of silicate is high.However, silicate is usually chosen for Sr isotope tracing in dust.The Sr isotopic composition varies with grain size,which is known as the grainsize effect.The fraction ＜2 μm has the highest Sr isotopic composition,which affects the Sr isotopic composition in bulk samples.The Sr isotopic composition of a certain grainsize fraction has very good tracing effect. Tracing dust origin using Sr isotope of carbonate has shown that carbonate in different desert of North China has different Sr isotopic composition, depending on geological settings and chemical weathering.