咸阳市区黄土显微结构研究

应用扫描电镜对咸阳市区黄土微结构进行研究,发现市区黄土的微结构特征在平面上随地形地貌不同而异,在剖面上随土层及深度不同而变化。在同一剖面上,黄土层与古土壤层的微结构差异最为明显,黄土层以支架大孔一镶嵌微孔半胶结式结构为主,古土壤以絮凝一凝块胶结式结构为主。在地貌单元上,渭河三级阶地、二级阶地黄土微结构较为疏松,主要为支架大孔一镶嵌微孔半胶结结构,一级阶地黄土微结构较为致密,主要为镶嵌微孔胶结式结构和絮凝胶结式结构。黄土微结构特征沿黄土剖面垂直方向上及沿地貌单元平面上的变化,主要是受黄土堆积环境、成土环境及埋藏环境共同作用的结果。

Study on Micro-structures of Loess in the Xianyang Downtown Area

Micro-structural characteristics of loess in the Xianyang downtown area were revealed using scanning electron microscope.Results show that loess microstructures are horizontally different with different landscape u- nits,and vertically vary with different loess layers.The micro-structural difference between loess layers and pale- osols in a given profile is most obvious.Loess layers mainly have supporting-macrospore and mosaic-microspore se- mi-cementation structures,whereas paleosols mainly have flocculent and coagulum cementation structures.Within a landscape unit,loess in the third and second terraces of the Weihe River is mainly characterized by supporting- macrospore and mosaic-microspore semi-cementation structures,and loess in the first terrace,by mosaic-microspore and flocculent cementation structures.Structure characteristics are mainly controlled by the environments of sedi- mentation,soil formation and loess burying.