兰州—民和盆地第三纪沉积特征及环境

Tertiary sedimentary features and environment of the Lanzhou-Minhe basin

在野外区域地质调查的基础上 ,通过岩性、沉积构造、古流向、垂向序列、沉积体三维形态和组合及室内粒度分析、扫描电镜分析等 ,于研究区第三纪地层中识别出了三角洲相、三角洲平原相、河流相、湖泊相、冲积扇相及风成砂丘。系统地研究了盆地的垂向充填序列 ,并且就对应的环境演变进行了较详细的探讨。

On the basis of the field regional geological surveys and through studies of the lithology, sedimentary structures, paleocurrent direction, vertical sequence and three dimensional shape and association of sedimentary units and grain size analysis and scanning electron microscope analysis, the delta facies, delta plain facies, fluvial facies, lacustrine facies, alluvial facies and eolian sand dunes are distinguished in Tertiary strata of the Lanzhou Minhe basin. The authors made a systematic study of the vertical infilling sequence of the basin. Moreover, the corresponding environmental evolution is discussed in detail.