摘要
通过对钻孔样品的粒度、层理揭片、矿物、微体古生物、孢粉、地球化学元素及古地磁等项目的实验室分析,着重探讨长江河口地区第四纪古地理、古环境变迁特征和长江三角洲的发育过程。
The Quaternary sedimentary strata in the Changjiang River estuarine region is no less than 250m in thickness. The lowest boundary corresponds to the Gauss/Matuyama, referred to 2.48 million YBP. During the early Pleistocene period, there existed colder and warmer climate, the sedimentaryenvironment was mainly characterized by fluvial with sporadic in fluen-ces of transgression, with the time increasing into mid-Pleistocene, the climate variation was relatively gentle, and the transgression influences became gradually increased. Sea water primarily invaded viapaleochannels and the studied area, as a result, was drowned as a former estuary. The climate veriation in the late Pleistocene was much drastic. Though sea level having several times of rising and falling in this period, the paleoground was not exposed out of water until the Wurm Glaciation. In this time took place the transition from shallow sea environment to coastal plain. Holocene climate was getting warmer and responding sea level rose nearly as high as the present time in the later Early Holocene when the Changjiang River with its large amount of fluvial input took the present channel into the sea, and started the deltaic construction.
出处
《地理学报》
EI
CSSCI
CSCD
北大核心
1991年第4期436-448,共13页
Acta Geographica Sinica
关键词
长江
河口
古地理
古环境
第四纪
Changjiang River Delta
Quaternary
Plaeogeography Paleoenvironment
