下扬子地区晚白垩世浦口期沉积古地理及地质背景

Sedimentary Paleogeography and Geological Background in the Pukou Stage of Late Cretaceous Period in the Lower Yangtze Area

浦口期沉积范围遍及下扬子区。岩性组合南北分带:南部残留层薄且颗粒粗,北部残留层厚且颗粒细。沉积相类型包括:冲积扇相、扇三角洲相、滨湖相、浅湖相、深湖相。改造该区沉积盆地外貌的是南象运动和燕山运动的Ⅰ幕、Ⅳ幕和Ⅴ幕。古地理演化以库拉太平洋板块向NNW向消减作用为地质背景。

The sedimentary rocks formed in Pukou stage of Late Cretaceous period are distributed widely in the Lower Yangtze area. There occur different rock assembles. Remnant rocks in the southern zone are thin and fine, while in the northern zone thick and coarse. The sedimentary facies includes alluvial fan, fan-delta, offshore lake, shallow lake and deep lake facies. The sedimentary basin was rebuilt by the Nanxiang movement and stage Ⅰ ,Ⅳ, Ⅴ of Yanshan movement. The evolution of palaeogeography in this region took place under the background of subduction of the Kula- Pacific plate in NNW direction.