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通过对泾河流域广泛的野外考察,在泾河下游高陵县段发现了典型的全新世古洪水滞流沉积剖面,系统地进行采集样品和粒度成分、磁化率、烧失量、吸湿水含量等多指标分析。从沉积学角度将古洪水滞流沉积物与全新世风成黄土和土壤进行对比,证明了该剖面所夹古洪水滞流沉积物的性质为细砂质粉砂,属于河流洪水悬移质泥砂沉积物。根据地层结构及与流域内其它剖面的对比,结合OSL测年数据,确定泾河在全新世中期4200~4000 a B.P.发生了第1期古洪水事件,在全新世晚期3200~2800 a B.P.发生了第2期洪水事件。这些古洪水事件都发生在全球性气候突变转折时期,表明在这些时期气候极端恶化,变率增大,洪水和干旱事件皆有发生。该研究对于泾河防洪减灾、水资源开发利用,对于揭示水文系统对于全球变化的响应规律,具有重要的科学意义。
Through extensive field investigation in the Jinghe River Basin, a typical Holocene flood flood sediment profile was found in the Lower Reaches of Jinghe River. Samples and grain size fractions, magnetic susceptibility, loss on ignition and water absorption capacity were systematically collected indicator anaysis. From sedimentology, the sediment of flood flood is compared with Holocene aeolian loess and soil, and it is proved that the sediment of the flood flood in the section is fine sandy silt, which belongs to sediment deposition of flood suspended sediment Things. According to the stratigraphic structure and comparison with other sections in the basin, combined with the OSL dating data, it is confirmed that the first ancient flood event took place in 4200 ~ 4000 a BP in Jinghe during the mid-Holocene. In the late period of the Late Holocene 3200 ~ 2800 a BP occurred No. 2 flood incident. All these ancient flooding events took place during the transitional period of global catastrophe, indicating extreme extreme weather deterioration, increasing variability and flood and drought events during these periods. This study has important scientific significance for the flood control and disaster reduction of Jinghe River, the development and utilization of water resources and revealing the response rules of the hydrological system to the global change.