地理学报 ›› 2009, Vol. 64 ›› Issue (3): 331-338.doi: 10.11821/xb200903008

• 地貌演变 • 上一篇    下一篇

末次盛冰期长江南京段河槽特征及古流量

曹光杰1, 王建2, 张学勤1, 屈贵贤2, 白世彪2, 龚小辉2   

  1. 1. 临沂师范学院实验与教育技术中心,山东临沂276005;
    2. 南京师范大学地理科学学院,南京210097
  • 收稿日期:2008-10-25 修回日期:2008-12-01 出版日期:2009-03-25 发布日期:2010-08-03
  • 作者简介:曹光杰(1964-),男,博士,教授,研究方向环境变化与机制。E-mail: guangjiecao@163.com
  • 基金资助:

    国家重点基础研究发展规划项目(2003CB415201-8);国家自然科学基金项目(40871010)

Characteristics and Runoff Volume of the Yangtze River's Paleovalley at Nanjing Reach in the Last Glacial Maximum

CAO Guangjie1, WANG Jian2, ZHANG Xueqin1, QU Guixian2, BAI Shibiao2, GONG Xiaohui2   

  1. 1. Experiment & Education Technology Center,Linyi Normal University,Linyi 276005,Shandong,China;
    2. School of Geography,Nanjing Normal University,Nanjing 210097,China
  • Received:2008-10-25 Revised:2008-12-01 Online:2009-03-25 Published:2010-08-03
  • Supported by:

    National Basic Research Program of China. No.2003CB415201-8;National Natural Science Foundation of China. No.40871010

摘要:

根据南京长江大桥、三桥、四桥的地质钻孔资料, 绘制南京段长江古河槽地质剖面示 意图。对拟建南京长江四桥附近的四个钻孔进行了采样分析, 从钻孔沉积物样品的14C 年代及阶地形成时间, 可以判断, 南京段约-60m~-90m 的深槽为末次盛冰期时的长江河槽。钻孔 揭示, 南京段长江古河槽狭窄陡峭, 呈V 型, 在南京长江大桥附近形成局部深切。根据长江三桥、长江大桥附近古深槽断面形态及底部沉积物颗粒级配, 选用沙莫夫公式、河海大学公式等, 计算了末次盛冰期时河槽底部的泥沙起动流速及断面平均流速。根据流量—流速—过水断面之间的关系式, 计算得出末次盛冰期时长江的流量约为12000~16000m3/s。

关键词: 古河槽, 流速, 流量, 末次盛冰期, 长江南京段

Abstract:

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), we can 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 LGM was calculated with Vcetc., 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 12000~16000 m3/s according to the relationship of discharge, velocity of flow and cross-section.

Key words: The Last Glacial Maximum, Nanjing reach of the Yangtze River, paleovalley, velocity of flow, runoff volume