| 端元分析在长江武汉段古洪水识别中的应用 |
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| 引用本文： | 朱海,张玉芬,李长安.端元分析在长江武汉段古洪水识别中的应用[J].沉积学报,2020,38(2):297-305. |
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| 作者姓名： | 朱海 张玉芬 李长安 |
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| 作者单位： | 1.中国地质大学(武汉)地球物理与空间信息学院, 武汉 430074 |
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| 基金项目： | 国家自然科学基金项目41672355国家自然科学基金项目41871019国家自然科学基金项目41671011武汉市多要素城市地质调查示范项目WHDYS-2018-004武汉市多要素城市地质调查示范项目WHDYS-2018-007 |
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| 摘 要： | 端元建模分析能够从具有复杂粒度分布特征的沉积物中提取出代表不同沉积动力过程的端元，进而对区域古洪水期进行揭示。以具有代表性的长江堤后湖泊ZK145钻孔晚第四纪沉积物为例，采用特征向量旋转算法对该钻孔粒度资料进行了端元建模分析。结果显示，可分离出4个具有明确地质意义的端元:EM1代表河流冲积砂；EM2代表经流水作用的细砂；EM3、EM4代表静水湖泊沉积。利用钻孔中粗粒端元组分(EM1、EM2)的含量结合磁化率指标，在湖相沉积阶段(22.9~3 m)识别出了9期特大古洪水。端元分析为长江堤后湖泊的古洪水研究提供了一种新的思路和方法，同时为古洪水的反演创造了条件。
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| 关 键 词： | 长江中游地区 湖相沉积 古洪水 端元分析法 |
| 收稿时间： | 2019-01-22 |
The Application of End-member Analysis in Identification of Paleo Floods in Wuhan Section of the Yangtze River |
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| Institution: | 1.Institute of Geophysics and Geomatics, China University of Geosciences(Wuhan), Wuhan 430074, China2.School of Earth Sciences, China University of Geosciences(Wuhan), Wuhan 430074, China3.Hubei Key Laboratory of Critical Zone Evolution, China University of Geosciences(Wuhan), Wuhan 430074, China |
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| Abstract: | The end-member modeling analysis can extract the end-members representing different sedimentary dynamic processes from the sediments with complex particle size distribution characteristics, revealing the paleo-flood period in the middle reaches of the Yangtze River. Taking the representative Quaternary sediments of the ZK145 borehole in the lake behind the Yangtze River's natural embankment as an example, the eigenvector rotation algorithm was used to analyze the end-member modeling of the borehole grain data. The study shows that four end-members with geological significance can be isolated:EM1 represents river alluvial sand; EM2 represents fine sand with through which water flows; EM3 and EM4 represent hydrostatic lake sedimentation. Using the content of coarse-grained endmembers(EM1, EM2)in the borehole combined with the magnetic susceptibility index, 9 paleo-floods were identified in the lacustrine sedimentary stage. The end-member analysis provides new methods and new ideas for the study of lacustrine paleo-floods after the Yangtze River embankment and, at the same time, created conditions for the inversion of paleo-floods. |
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