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    黄河故道区晚全新世沉积记录及其对洪水灾害事件的响应

    Late Holocene sedimentary records along the abandoned channel areas of the Yellow River and their response to flood hazards

    • 摘要:
      研究目的 黄河故道区蕴藏了丰富的古洪水灾害信息,深入挖掘地层中相应的沉积记录,有助于扩展黄河流域洪水记录的时空范围,增进对洪水灾害的科学认识。
      研究方法 本文选取河北大名龙王庙剖面作为黄河故道区的典型代表剖面,利用光释光、14C、粒度和地球化学元素等测试手段,综合对比洪水史料记载与区域研究成果。
      研究结果 研究认为:(1)古土壤、湖沼相沉积、泛滥沉积与平流沉积物之间存在一定的继承性与相关性;(2)晚全新世以来研究区内4次主要的洪水沉积单元,分别对应了周、西汉、北宋和明朝的异常洪水事件;(3)人类活动对流域洪水灾害产生了一定的影响,由高频低能的季节性洪水转变为低频高能的异常洪水事件。
      结论 该项研究基本查明了黄河故道区不同沉积相的岩性特征及环境代用指标特征,探讨了人类活动对洪水特征的影响,为黄河故道区洪水灾害沉积记录的判别与重建提供了理论参考和示范,同时有助于进一步深入认识黄河流域洪水灾害的过程及演化机制。

       

      Abstract:
      This paper is the result of hydrogeological survey engineering.
      Objective Late Holocene sedimentary records along the abandoned channel areas contain lots of paleoflood information in the lower Yellow River, which can help to extend extreme flood records, and are of great value in understanding flood hazard patterns.
      Methods This paper selects Longwangmiao (LWM) profile (located in Daming County), Hebei Province, as the typical paleoflood section in the lower Yellow River. Luminescence dating, radiocarbon dating, gransize, and geochemistry analyses are combined with a synthesis of historical flood records and regional previous works.
      Results The study concluded that: (1) Different facies in LWM profile, including paleosols, lacustrine deposits, overbank deposits, and slackwater deposits, have some close relationships with the others. (2) Four major flood deposits during the late Holocene are corresponding to four abnormal flood events in Zhou Dynasty, Western Han Dynasty, Northern Song Dynasty, and Ming Dynasty in this area. (3) Human activities have a profound impact on flood scale and frequency in the lower Yellow River, from seasonal floods to extreme floods.
      Conclusions The study identified the characteristics of different sedimentary facies on lithology and environmental proxies, and explored the influence of human activities on floods. It provides a reference for paleoflood research along the abandoned channels in the lower Yellow River, and helps to further understand the processes and evolutionary mechanisms of flood hazards in the Yellow River.

       

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