赣北黄茅潭湖泊沉积记录的240年以来古洪水事件

发布时间：2018-04-17 12:39

本文选题：湖泊沉积 + 洪水指标　；参考：《地理科学进展》2017年11期

【摘要】：古洪水研究是近几十年来全球变化研究的一个热点,同时也是难点。本文利用赣北黄茅潭的湖泊沉积,建立了小冰期以来全球变暖背景下的区域洪水记录。采用210Pb和137Cs方法厘定了地层年代,基于粒度与元素地球化学指标的对比分析,揭示了器测记录(1950年)以来指标记录的特点与区域日降水超过50 mm天数的关系,认为黄茅潭HMT-01孔粒度(包括粗粉砂+砂/粘土比值、平均粒径)和Zr/Rb、Ti/Rb、Zr/Fe比值可作为洪水指标记录,共识别出1950-2010年期间记载的13次洪水事件中的11次。基于这些指标记录及指标特点,共识别1769-1950年间由历史文献记录的31次洪水事件中的23次,识别率达74.2%。研究表明:(1)湖泊沉积中Zr/Rb、Ti/Rb、Zr/Fe比值和粒度参数(平均粒径、粗粉砂+砂/粘土)作为洪水指标,对洪水事件沉积有较好的指示作用,且Zr/Rb比值对洪水事件的检出率较高;(2)黄茅潭流域洪水发生频率暖期高于冷期;(3)年代际尺度上,1820s-1840s,1860s-1870s为19世纪冷期黄茅潭洪水高频期,这两个阶段对应东亚夏季风偏强,长江中下游地区降雨较多;20世纪赣北黄茅潭洪水基本随1920s-1940s,1980s-1990s两个变暖阶段而高频出现,与长江中下游大洪水演变特点基本一致。研究结果为利用湖泊沉积记录反演过去的洪水变化,延长洪水序列、认识洪水规律提供了一定的科学依据。
[Abstract]:The study of paleo-flood is a hot spot in the research of global change in recent decades, and it is also a difficult point.In this paper, the regional flood records under the background of global warming since the Little Ice Age have been established by using the lake sediments of Huangmaotan, northern Jiangxi.The stratigraphic dating was determined by 210Pb and 137Cs methods. Based on the comparative analysis of grain size and element geochemical indexes, the relationship between the characteristics of the index records since the instrument record (1950) and the days of daily precipitation exceeding 50 mm in the region was revealed.It is considered that the HMT-01 pore size (including coarse silt / clay ratio, mean particle size) and Zr / R / R / R ~ (b) / Fe ratio of HMT-01 pore in Huangmaotan can be used as flood index records, and 11 of the 13 flood events recorded during 1950-2010 are identified.Based on the records of these indexes and their characteristics, 23 of the 31 flood events recorded by historical documents in 1769-1950 were identified, and the recognition rate was 74.222.The results show that the ratio of Zr / Rb / Ti / RB / Zr / Fe and the grain size parameters (mean particle size, coarse silt / clay) in lake sediments are good indicators for flood event deposition.Moreover, the detection rate of Zr/Rb ratio to flood events is higher than that in the warm period of Huangmaotan Basin. The frequency of flood occurrence in Huangmaotan basin is higher than that in cold period.) on the Interdecadal scale, 1820s-1840s / 1860s-1860s-1860s-180s is the high-frequency flood period of Huangmaotan flood in the cold period of 19th century, which corresponds to the strong summer monsoon in East Asia.In the middle and lower reaches of the Yangtze River, the flood in Huangmaotan, northern Jiangxi Province, occurred at high frequency with the two warming stages of 1920s-1940s / 1980s-1990 s in the 20th century, which is basically consistent with the characteristics of the evolution of the flood in the middle and lower reaches of the Yangtze River.The results provide a scientific basis for retrieving the past flood changes, prolonging the flood sequence and recognizing the flood regularity by using the lake sediment records.
【作者单位】：江西师范大学地理与环境学院;中国地质大学地球科学学院;鄱阳湖湿地与流域研究教育部重点实验室;
【基金】：江西省重大生态安全问题监控协同创新中心项目(JXS-EW-00) 鄱阳湖湿地与流域研究教育部重点实验室(江西师范大学)开放基金项目(ZK2013003)~~
【分类号】：P532;TV122.2

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