南京附近古砾石层的相标志及沉积环境分析

南京附近的古砾石层是组成该区新生代地层重要岩石类型之一。据砾石成分与附近基岩地层岩性对比,证实砾石以近源为主,也有些为远源;借助古砾石层中的相标志及其垂向剖面结构特征,可认为当时古长江河谷宽阔,古河道内由砂砾组成的心滩发育,呈现辫状河流沉积特征,遂成为今日树枝状展布的古砾石层。

The Facies of the Ancient Gravel Beds in the Suburbs of Nanjing and the Sedimentary Environment

The ancient gravel beds in the suburbs of Nanjng is one of the important types of rock of the Cenozoic era.According to the comparison between the compostion of the gravels and the lithology of the bedrock strata this paper proves that most of gravel came from the nearly source, the rest came from a distant source. Based on the ancient gravel section texture. The authors believe that the ancicnt Yangtze Riv er was broad and the mid-bars, composed of sands and gravel,was developed in the river fossil course,forming characteristically braided river, so the dendritic ancient gravel bodies were formed as seen today.