地理学报 ›› 1982, Vol. 49 ›› Issue (2): 174-182.doi: 10.11821/xb198202007

• 论文 • 上一篇    下一篇

长江三峡卵石推移质来源的研究

林承坤   

  1. 南京大学
  • 出版日期:1982-04-15 发布日期:1982-04-15

THE SOURCE OF GRAVAL BED LOAD OF THE YANGTZEGORGES

Lin Cheng-ken   

  1. Department of Geography, Nanjing University
  • Online:1982-04-15 Published:1982-04-15

摘要: 长江三峡宜昌以上流域面积100万平方公里。长江三峡卵石推移质来源的分析,实际上是研究卵石推移质的流域产沙的问题。

关键词: 卵石推移质, 补给区, 重量百分数, 长江三峡, 宜昌, 采样点, 金沙江, 万县, 新构造运动, 进口段

Abstract: Investigations and studies on the geology and geomorphology of the Upper Yangtze River indicate that the petrographic classification and composition of the gravel bed load in the river depends on the geological and geomorphological conditions of river basin. According to the regional geological and geomorphological characteristics and their effects on the lithologieal character of the gravel bed load the source of the gravel bed load can be divided into 4 supplementary regions, namely, the Middle and lower reaches of the Jinsha Valley and middle reaches of Yalong valley; the Upper reaches of the Mian Valley and the Dadu Valley; the Upper reaches of the Jialing and the Yangtze Gorges regions.After lithogical statistical analysis of nearly 125,000 grain samples collected by the author during his three geological and geomorphologial field investigation indicate that the lithologieal characters of the gravel bed load are governed by the geological and geomorphological conditions of the watershed. Hence, a mathematical model is set up to calculate the source of the bed load by using the percentages of petrographic classi-fication of the bed load in the main districts and the confluences of the valley (Eq. (2)). The result shows that 69.9% of the source of gravel bed load at Wanxian station, situated at the entry reach of the Groges, comes from the Middle and Lower reaches of the Jinsha valley and Middle reaches of Yalong Valley, 18% from the Upper reaches of the Mian Valley and the Dadu Valley, 12.1% from the Upper reaches of the Jialing Valley; and there are about 57.1% of the total gravel bed load at Yichang Sta-tion, which is located below the Gorges, comes from the Gorges Eegion itself, and 42.9% comes from the Upper Reaches above Wanxian Station.