同步辐射X射线荧光微探针技术测定太古宙条带状硅铁建造中硅质条带及包裹体的微量元素

Measurements of trace elements in silica of Early Archean's banded iron formation and primary inclusion in them by Synchrotron Radiation X-ray fluoresence microprobe techniques

通过对35亿年前曹庄岩组的条带状硅铁建造(BIF)的硅质条带以及石英中包裹体微量元素的分析,初步探讨了35亿年前的 BIF 形成时期海洋的化学成分。结果表明太古宙海洋中贫乏 P、V、Cu 等生命元素,限制了真核生物的发展,而其它微量元素高度富集,为化学自养细菌提供了良好的环境。在 BIF 的硅质条带的形成过程中,微量元素的含量受到磁铁矿沉积吸附的强烈控制。

We study the content of trace elements in silica of Early Archean＇s banded iron formation and primary inclusion in them by Synchrotron Radiation X-ray fluoresence microprobe techniques, and conclude the chemistry of sea water before 3.5Ga. We find the absent of K, P, Vet al. , to constraint the advance of life. But the other elements are abundant, and it is fit for bacteria. The content of trace elements are adsorbed by Fe-oxide sediment, so the trace elements content in early Archean sea was controlled by Fe-oxide sediment and bacteria activity.