河北平泉中元古代高于庄组和杨庄组地球化学特征

The Geochemical Characters of the Gaoyuzhuang and Yangzhuang Formations of Mesoproterozoic in Pingquan County, Hebei Province

根据河北平泉地区中元古代高于庄组和杨庄组中 21 件岩石样品分析结果,显示常量元素和微量元素的含量在纵向上的演变规律不明显,但各种元素含量在岩石地层界线均有明显变化,表明地球化学特征可作为划分沉积地层的标志或对已划分的地层界线进行优化。此外,据 w( CaO)/w(MgO)值、w(Ca)/w(Ca+Fe)值、w(Sr)/w(Ba)值及V、Pb、Co、Ni和 Ti等元素特征分析,高于庄组与杨庄组的沉积环境有极大的差异。高于庄组为远岸深水海洋环境下的沉积,陆源碎屑供应匮乏;而杨庄组为干热气候下的近岸海洋环境沉积,具有较多的陆源碎屑物质供应。

Chemical analysis of 21 rock samples from the Gaoyuzhuang and Yangzhuang Formations of Mesoproterozoic Era in Pingquan County, Hebei Province reveals that the change in major and trace elements in vertical direction of the section is ruleless. However, apparent content changes in major and trace elements are obvious at the lithostratigraphic boundary of the strata, revealing that these geochemical characters of the strata can be used as indicator while dividing sedimentary strata or optimizing lithostratigraphic boundary. Besides, based on character analysis of CaO/MgO, Ca/(Ca+Fe), Sr/Ba and V, Pb, Co, Ni, Ti of the strata, the Gaoyuzhuang Formation and Yangzhuang Formation are of great difference in their sedimentary environment. The sedimentary environment of the Gaoyuzhuang Formation belongs to deep water and far from coast with less terrigenous clast supply while that of the Yangzhuang Formation was under shallow water and near coast conditions with more terrigenous clast supply.