Characteristics and Runoff Volume of the Yangtze River’s Paleovalley at Nanjing Reach in the Last Glacial Maximum
详细信息
- 责任者：Cao Guangjie (Experiment & ; Education Technology Center ; Linyi Normal University ; Linyi 276005 ; China) ; Wang Jian
- 刊名：Acta Geographica Sinica
- 出版年：2009
- 卷期：64(3)
- 关键词：末次冰期 ; last glacial age ; 古水流 ; paleocurrents ; 长江 ; Yangtze River
- 页码：p.331-338
- 图表：2 illus., 3 tables, 29 refs.
- 分类号：1400
- issnNo：ISSN0375-5444
- isbnNo：CN11-1856/P
摘要
Three cross-sections of paleovalley depositional sequences were established with references of hundreds of bore data and documents of the No.3, No.1 and No.4 Nanjing Yangtze River bridges. Through analyzing age results of 14C from samples of four drilling cores near the No.4 Nanjing Yangtze River Bridge （to be built）, the authors find that the time range of paleovalley is dated LGM at a depth of -60~-90 m near Nanjing. It is also indicated that the deep incised-valley channel was narrow and the river flew swiftly. The ancient Yangtze River deep channel presented partially and deeply incised features near the No.1 Nanjing Yangtze River Bridge. According to previous publications, much research has been done on the main paleochannel of the Yangtze River, but few results have been achieved on discharge estimation. In this paper, the incipient velocity and average velocity of the LGMwas calculated with Vc = 4.60d1/3h1/6, Vc = 1.28lg 13.15 dh95 gd, V ≈6.5u* dh90 , etc., in terms of the river shape, sedimentary grain size and sequences near the No.3 and No.1 Nanjing Yangtze River bridges. Moreover, the discharge in Nanjing reach of the Yangtze River during the LGM has been estimated to be around 12 000~16 000 m3/s according to the relationship of discharge, velocity of flow and cross-section.