湖泊沉积记录的古洪水事件识别及与气候关系

作为洪水灾害研究的延伸学科——古洪水研究,其所取得的大量研究成果基本都是基于河流古洪水水文学的研究。然而随着河流古洪水水文学科的发展,研究材料和方法的缺陷越来越凸显,而作为气候与环境变化信息重要收集器的湖泊沉积物在古洪水水文学上的研究可以弥补上述不足。本文重点综述了湖泊沉积物识别古洪水的方法以及古洪水与环境的耦合机制。主要分为两部分：其一,总结了湖泊洪水识别的4种方法,即湖泊沉积物岩性和粒径、地球化学指标、数学统计分析方法以及洪水与块体运动的甄别;其二,从成因上探讨了古洪水与大陆尺度大气环流变化、区域气候波动的遥相关性。最后,探讨了洪水事件和气候变化的具体物理机制,并对湖泊洪水与同区域河流洪水进行对比研究以及国内湖泊尤其高山地区湖泊洪水领域的研究等方面进行了展望。

Identification of Paleaoflood events by lacustrine archives and their links to climatic conditions

Palaeoflood hydrology, as an extended field of flood disaster research, has gained great achievements based on sedimentary records extracted from rivers. However, these river palaoeflood studies have limitations due to the short duration and incompleteness of sedimentary records. Lake sediments as a more efficient archive, however, often record a temporally complete palaeoflood sequence. This article reviews four most commonly applied methods to identify and reconstruct palaeofloods from lake sediments, that is, lithology and grain size, geochemical indicators, statistical analysis, and eliminating mass-movement from palaeoflood layers. Subsequently we explore the causal relationship between palaeofloods and change in continental scale atmospheric circulation and regional climate change. Finally, we discuss the prospects of several studies, including the physical mechanism of palaeoflood events and climate change, comparative study of lake palaeoflood records and regional river paleoflood records, and palaeoflood research in lakes, especially mountain lakes.