汝河全新世古洪水沉积学与光释光测年研究

发布时间：2019-01-23 07:28

【摘要】：汝河流域曾发生过堪称世界之最的"1975·8河南驻马店特大洪水垮坝事件",其洪水规模之大,受灾面积之广,受灾及死亡人数之多,震惊世界。因此探究汝河特大洪水事件的发生规律及其气候背景具有极其重要的科学价值。通过对汝河流域开展广泛细致的野外考察,在驻马店-遂平段第一级河流阶地前沿发现多处全新世古洪水滞流沉积物剖面,记录了流域发生的气候水文事件信息。最终选取汝河诸市乡地点(ZSX)全新世黄土土壤剖面进行系统采样,结合沉积学指标研究,准确鉴别出汝河ZSX黄土古土壤剖面中所夹三组古洪水滞流沉积物(slackwater deposits,SWD),为典型河流洪水悬移质泥沙沉积物。结合地球化学特征分析,确认三组古洪水SWD的物质是汝河上游流域发生特大暴雨洪水期间,流域地表土壤侵蚀与水土流失的产物。这三组古洪水滞流沉积物记录了末次冰消期和全新世发生在汝河流域的三期古洪水事件。结合典型剖面地层对比和应用SAR法对剖面关键沉积层位进行光释光测年(optical stimulated luminescence dating,OSL),建立了准确的地层年代框架。这三期古洪水事件分别发生在12000~11200aBP、4200~4000aBP、3200~3000aBP,皆发生在全球性气候突变或者转折时期,表明在这些时段季风气候变化异常,变率增大,洪水和干旱事件皆有发生。本研究对于淮河防洪减灾、水土保持及水资源开发利用,对于揭示区域气候水文变化与全球变化的响应规律,具有十分重要的科学意义和实践价值。
[Abstract]:The Ruhe River basin has been the world's most "1975 8 Zhumadian huge flood dam collapse incident", its flood scale, disaster area, the number of victims and deaths, shocked the world. Therefore, it is of great scientific value to study the occurrence law and climatic background of the Ruhe flood event. Through extensive and meticulous field investigation of the Ruhe River Basin, several sections of Holocene paleo-flood stagnant sediment were found on the front of the first-order river terrace in Zhumadian-Suiping section, and the information of climatic and hydrological events occurred in the basin was recorded. Finally, the (ZSX) Holocene loess soil profile in Zhushi and rural area of Ruhe was selected for systematic sampling, and three groups of paleo-flood stagnant sediments (slackwater deposits,SWD) were identified accurately by combining with the sedimentological index study in the Ruhe ZSX loess paleosol profile. It is a typical river flood suspended sediment. Based on the analysis of geochemical characteristics, it is confirmed that the material of three groups of paleo-flood SWD is the product of soil erosion and soil erosion in the upper reaches of the Ruhe River basin during the severe rainstorm flood. These three groups of paleo-flood stagnant sediments recorded the last ice extinction period and three paleo-flood events occurred in the Ruhe basin in Holocene. In combination with typical profile stratigraphic correlation and SAR method, an accurate stratigraphic chronological framework was established by means of (optical stimulated luminescence dating,OSL (optical emission dating) of the key sedimentary horizon of the section. These three paleo-flood events occurred in 12000 ~ 11200aBP ~ (4200) ~ 4000aBPN ~ (3000aBP), and all occurred in the period of global climatic abrupt change or transition, indicating that the monsoon climate change was abnormal and the variability rate was increased during these periods, both flood and drought events occurred. This study is of great scientific significance and practical value for flood control and disaster reduction, soil and water conservation and water resources exploitation and utilization in Huaihe River, as well as for revealing the response law of regional climate and hydrological change and global change.
【作者单位】：陕西师范大学地理科学与旅游学院;地理学国家级实验教学示范中心(陕西师范大学);西北大学城市与环境学院;
【基金】：国家自然科学基金项目(批准号:41771110,41601020) 中国博士后科学基金项目(2016M59289)共同资助的成果
【分类号】：P512.2;P534.632

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