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中国沙漠 ›› 2021, Vol. 41 ›› Issue (3): 92-100.DOI: 10.7522/j.issn.1000-694X.2021.00024

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基于沉积物理化性质的雅鲁藏布江中游粉尘物源研究

张焱1(), 马鹏飞2, 曾林2, 梁爱民3, 张正偲1()   

  1. 1.中国科学院西北生态环境资源研究院 沙漠与沙漠化重点实验室,甘肃 兰州 730000
    2.西藏自治区气候中心,西藏 拉萨 850000
    3.陕西师范大学,陕西 西安 710119
  • 收稿日期:2021-01-14 修回日期:2021-02-11 出版日期:2021-05-26 发布日期:2021-05-26
  • 通讯作者: 张正偲
  • 作者简介:张正偲(E-mail: zhangzhsi@lzb.ac.cn )
    张焱(1998—),男,湖南湘西人,硕士研究生,主要从事沙尘释放方面的研究。E-mail: zhangyan98613@163.com
  • 基金资助:
    西藏自治区“十三五”重点规划项目(“雅江北岸易地扶贫搬迁区沙尘监测与预报预警系统建设”,“西藏主要地表特征科学考察及研究”);国家自然科学基金项目(41930640)

Study on silt and clay provenance in the Yarlung Zangbo River middle reaches using sediment physicochemical characteristics

Yan Zhang1(), Pengfei Ma2, Lin Zeng2, Aimin Liang3, Zhengcai Zhang1()   

  1. 1.Key Laboratory of Desert and Desertification,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
    2.Tibet Climate Center,Lhasa 850000,China
    3.Shaanxi Normal University,Xi’an 710119,China
  • Received:2021-01-14 Revised:2021-02-11 Online:2021-05-26 Published:2021-05-26
  • Contact: Zhengcai Zhang

摘要:

物源是风沙研究的主要内容。雅鲁藏布江中游风沙区是西藏自治区的主要沙丘分布区和受风沙灾害影响的主要区域。但目前对该地区沙尘物源的研究甚少,从而限制了我们对该地区风沙地貌形成演化过程、防沙治沙工程合理布局和沙尘暴预报预警工作的开展。沉积物理化性质是沉积物物源判别的主要证据。为此,收集了雅鲁藏布江中游河岸、河漫滩、河漫滩沙丘、林地和山麓沙丘沉积物样品,对其进行粒度、常量元素和微量元素(<63 μm)分析,对该地区沙尘物源进行判别。结果表明:(1)不同类型地表沉积物粒度特征存在明显空间差异。沙丘沉积物以>63 μm沙为主(>91%),而河岸和河漫滩粉沙和黏土含量与沙的含量几乎相同。(2)不同地表沉积物的常量元素相似。SiO2含量最大,MgO含量最小;Fe2O3在河岸、河漫滩和林地富集,而在沙丘亏损,其他元素均为亏损。(3)不同地表微量元素差异较大,Ti、Sr和Ba总体为亏损,其他元素为富集。(4)不同地表沉积物的元素比值和风化过程相似,说明了研究区地表沉积物具有相同的物质来源。河岸和河漫滩具有形成风沙灾害的物质条件,是风沙灾害的主要物源。

关键词: 雅鲁藏布江, 沉积物, 理化性质, 物源

Abstract:

Sediment provenance is one of the issues for aeolian research. Yarlung Zangbo River middle reaches is the main sand distribution region, and also is the aeolian disaster region. However, there is few research had been done on the sediment provenance in the Yarlung Zangbo River, which limited our knowledge on aeolian geomorphology formation and development, aeoian disaster prevention and dust storm forecasting. Sediment physicochemical property had been widely used to identify sediment provenance. Therefore, we collected sediment on river bank, sand dunes, and floodplain samples from field investigations. Sediment grain size and selected < 63 μm sediment chemical properties were analyzed. The results indicated that: (1) Sand, silt and clay contents are different for landscapes. The silt and clay content are similar for river bank and floodplain, and sand content is the maximum in sand dunes. (2) Sediment geochemical characteristics are similarities for five landsacpes. Major elements are mainly deficit, and SiO2 content is the largest for all samples, and MgO content is the smallest. (3) Trace elements are mainly enriched. (4) Ratios of selected elements are similar for five landscapes, which means that sediment provenance is similar for all landscapes. Therefore, river bank and floodplain has the sediment conditions for aeolian disaster, and it’s a main dust sources for aeolian disaster.

Key words: Yarlung Zangbo River, aeolian sediment, physicochemical characteristics, sediment provenance

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