地理科学进展 ›› 2010, Vol. 29 ›› Issue (7): 840-846.doi: 10.11820/dlkxjz.2010.07.010

• 气候与水文过程 • 上一篇    下一篇

渭河天水峡谷全新世特大洪水水文学研究

朱向锋1, 黄春长1,2, 庞奖励1, 查小春1   

  1. 1. 陕西师范大学旅游与环境学院,西安 710062|
    2. 中科院地球环境研究所黄土与第四纪地质国家重点实验室, 西安 710075
  • 收稿日期:2009-09-01 修回日期:2010-01-01 出版日期:2010-07-25 发布日期:2010-09-02
  • 作者简介:朱向锋(1977-),男,陕西临潼人,硕士,主要研究方向为资源开发与环境演变。E-mail:zhuxiangfeng@126.com.
  • 基金资助:

    国家自然科学基金项目(40771018), 陕西省自然科学基金项目(2006D01),中科院黄土与第四纪地质国家重点实验室基金(SKLLQG 0609), 中央高校基本科研业务费专项资金资助(GK200901007),陕西省教育厅自然科学研究计划资助项目(09JK330).

Palaeo-Hydrologrcal Studies of the Holocene Extreme Floods in the Tianshui Gorges of the Weihe River

ZHU Xiangfeng1, HUANG Chunchang1,2, PANG Jiangli1, ZHA Xiaochun1   

  1. 1. College of Tourism and Environmental Sciences, Shaanxi Normal University, Xi'an 710062, China|
    2. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth and Environment Research, CAS, Xi'an 710075, China
  • Received:2009-09-01 Revised:2010-01-01 Online:2010-07-25 Published:2010-09-02

摘要:

古洪水水文学是全球变化科学领域的新兴学科。通过对渭河上游天水段基岩峡谷的详细考察,对在杜家坪村附近发现的全新世古洪水滞流沉积剖面进行了深入研究。沉积学观察和分析结果表明这些沉积物为洪水悬移质泥沙沉积形成,因而其主要成分为粉沙,分选良好。其磁化率值很低,表明它们是全新世晚期的沉积物,还没有受到风化成壤作用的改造。通过与其下游宝鸡峡全新世古洪水沉积剖面的地层学和考古年代学对比,确定其发生的时代在3200~3000a BP之间,即全新世大暖期结束之时。利用古洪水水文学方法,求出该组古洪水沉积层所记录的特大洪水的洪峰流量介于23460~25480m3/s之间。同时,通过进一步分析验证,表明对于古洪水洪峰流量计算结果是可靠的。本研究获得了渭河万年尺度特大洪水的水文学数据,延长了洪水水文数据序列,在工程水文领域有重要应用性价值,对于揭示全球变化的水文响应具有重要的科学意义。

关键词: 沉积物, 古洪水, 全新世, 水文学, 渭河

Abstract:

Palaeoflood hydrological studies were carried out at the upper reach gorges of the Weihe River. Palaeoflood slackwater deposits were found at the DJP site in the Tianshui gorges of the mainstream of the river. Analysis of the grain-size distribution indicates that these SWD consist of silts and clayey silts, sourced from the suspended sediment load of the floodwater. The low magnetic susceptibility indicates they are fresh deposits without weathering and pedogenic alteration. Stratigraphic correlation with the SWD discovered downstream at the Guchuanzhen site of the Weihe River shows that these extreme floods occurred between 3200-3000 a BP at the end of the mid-Holocene climatic optimum. The reconstructed peak discharges of the palaeofloods range from 23,460 m3/s to 25,480 m3/s which are much larger than gauged floods. These results were further tested and proved to be reliable with reconstruction of the modern floods at the same reach. This research is of great importance for hydrological engneering and flood mitigation. And it is also very important for the establishment of the relationships between extreme flood events and global climate change.

Key words: Holocene, hydrology, palaeoflood, slackwater deposits, Weihe River