【摘要】 通过对泾河流域广泛深入的考察,在泾河中游彬县至永寿基岩峡谷河段发现典型的全新世古洪水平流沉积剖面,进行了古洪水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具有平流沉积特征,为典型的洪水平流沉积物。根据地层学对比和剖面自身龙山文化晚期陶片、烧土等文化遗物分析,确定泾河在4200～4000 a BP发生了特大洪水事件,并利用沉积学和水文学原理恢复其水位,计算出古洪水洪峰流量为19490～22040m3/s。同时,通过恢复现代大洪水、洪峰流量与流域面积关系对这种方法和古洪水洪峰流量计算结果进行了验证。不仅延长泾河洪水水文数据序列到万年尺度,而且为沿泾河的水利水电和交通工程建设及沿岸地区城镇的防洪减灾提供了重要的基础数据,具有重要的科学意义和应用价值。更多还原

【Abstract】 Through investigation of the middle reaches of the Jinghe River, we choose the slackwater deposits for palaeohydrology study. On the basis of field survey, samples of the slackwater deposits were collected and the grain-size distribution, the magnetic susceptibility variation, the loss on ignition and the content of calcium carbonate were determined. All of these indexes showed that the slackwater deposits were typical in the study area. According to the stratigraphic correlation and cultural remains including fragments of pottery and burnt earth, we identified the corresponding palaeoflood which occurred in the late period of Longshan Culture (4200-4000 a B.P.). Supported by the hydrological technique, we reconstructed that the peak discharges of the palaeofloods were 19490-22040 m3/s. Meanwhile, reconstruction of modern gauged flood proved the hydrological method was reliable. And the relationship between drainage area and flood peak discharge illustrated that the results were reasonable. Thus, the results prolong the flood data sequence of Jinghe River and provide significant data for engineering construction, flood control and disaster alleviation in the middle reaches of the Jinghe River.更多还原