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通过对黄河中游晋陕峡谷段的考察,在多个地点发现全新世古洪水滞流沉积层。选择壶口段左岸岩棚内典型的古洪水滞流沉积剖面进行沉积学和水文学研究。对于采集的全新世地层剖面序列样品,进行粒度成分、磁化率、烧失量、CaCO3含量等分析,从沉积学角度证明了研究剖面所夹洪水沉积物为典型的古洪水滞流沉积物,记录了全新世两个时期的特大洪水事件。通过地层学对比分析和OSL测年,确定其分别发生在全新世早期—中期转折阶段,和中期—晚期转折阶段。利用沉积学和水文学原理恢复古洪水水位,计算出第一组古洪水洪峰流量为27490m3/s、27830m3/s、28570m3/s,第二组为40920m3/s。本文的研究发现全新世特大洪水事件,并且恢复了其水文特征数据,对于揭示黄河水文过程对于全球变化的响应规律具有重要的科学意义,对于水利工程建设具有重要的现实意义。
Through the investigation of the Jin-Shan Canyon section in the middle reaches of the Yellow River, the Holocene pale flood stagnant sediments were found in many places. Sedimentology and hydrology studies were conducted on the typical paleo-flood stagnant sediments in the left bank of Hukou section. For the collected samples of Holocene stratigraphic sequence samples, we analyzed the grain size composition, magnetic susceptibility, loss on ignition, CaCO3 content and so on. It is proved from sedimentology that the flood sediment trapped in the study section is typical paleo-flood stagnant sediment, In the Holocene two major flood events. Through stratigraphic correlation analysis and OSL dating, it is confirmed that they occur in the early-mid-Holocene transitional stage and the mid-late transitional stage, respectively. Using the principles of sedimentology and hydrology to restore the ancient flood water level, the first flood peak flood discharge was calculated as 27490m3 / s, 27830m3 / s, 28570m3 / s and the second group was 40920m3 / s. The discovery of the Holocene catastrophic flood events and restoration of hydrological characteristics data in this paper will be of great scientific significance for revealing the response of the Yellow River hydrological processes to global changes and have important practical significance for the construction of water conservancy projects.