地理学报 ›› 1995, Vol. 50 ›› Issue (5): 459-463.doi: 10.11821/xb199505009

• 论文 • 上一篇    下一篇

末次冰期时存在入海的长江吗?

李从先, 张桂甲   

  1. 同济大学海洋地质系, 上海 200092
  • 收稿日期:1994-04-01 修回日期:1994-12-01 出版日期:1995-09-15 发布日期:1995-09-15
  • 基金资助:
    国家自然基金

A SEA-RUNNING CHANGJIANG RIVER DURING THE LAST GLACIATION?

Li Congxian, Zhang Guijia   

  1. Department of Marine Geology. Tong ji University, Shanghai. 200092
  • Received:1994-04-01 Revised:1994-12-01 Online:1995-09-15 Published:1995-09-15

摘要: 钻孔揭示现今长江三角洲地区存在自镇江、扬州向东南延伸至海的古河谷,其中的充填物为河流相、浅海相和三角洲相,沉积时间为冰后期,古河谷当形成于末次冰期低海面之时。研究地区巨大古河谷的存在说明末次冰期低海面时长江仍为入海河流。

关键词: 长江, 古河谷, 末次冰期, 低海面

Abstract: Numerous boreholes demonstrate that there is indeed an incised paleo-valley stretching into the East China Sea from Zhenjiang and Yangzhou at the apical area of the Changjiang Delta. The filling deposits in the paleo-valley are of fluvial. neritic and deltaic facies. The fluvial sedimentary unit composed of sand with gravels and sand at the low part, and of grey sandy clay with sandy lenses at the upper part, is a fining-upward sequence with erosional boundary at its bottom. The unit was formed by retrogressive aggradation in process of the postglacial transgression. The 14C datings show that the fluvial unit was deposited during the postglacial period while the sea level rised rapidly and the paleo-valley was incised when the sea level lowly standed. The fluvial facies is overlain by the neritic facies which consists of grey mud rich in marine microfossils-.The deltaic facies including mouth bar sand and distributary sandy clay covers the neritic facies nearly in the limits of the paleo-valley. The presence of enormous paleo-valleys support that the Changjiang River was still sea-running during the period of sea lowstand in the last giaciation.

Key words: Changjiang River, paleo-valey, last glaciation, sea level lowstand

中图分类号: 

  • P534.631