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通过对泾河下游的野外考察,在高陵县杨官寨仰韶文化遗址东南部发现夹有典型的古洪水滞流沉积层的全新世黄土—古土壤剖面。利用单片再生剂量法(SAR)测定了40～63μm粒径石英的光释光(OSL)年龄。从剖面获得的样品年龄数值处在2.27±0.06ka到14.26±0.58ka之间,且与地层深度表现出良好的对应关系。通过样品OSL年龄与其埋深的关系,结合粒度和磁化率数据地层对比,以及文化层考古年龄,确定了该全新世剖面的基本年代框架。研究结果表明,在4.20～4.00ka泾河流域发生了第一期多次古洪水事件,在3.20～2.80ka发生了第二期特大古洪水事件。这些古洪水事件与全球性气候突变事件同时发生,是泾河流域气候水文系统对于全球变化的响应。
Through the field investigation in the lower reaches of Jing River, the section of the Holocene loess-paleosol with typical paleo-flood stagnant sediments was found in southeastern Yangshao Culture Relics, Yangguangzhai, Gaoling County. Photoluminescence (OSL) age of 40 ~ 63μm quartz was measured by monolithic regeneration dose method (SAR). The age values of the samples obtained from the profile ranged from 2.27 ± 0.06 ka to 14.26 ± 0.58 ka and showed a good correspondence with the depth of the strata. Based on the relationship between OSL age and its burial depth, the stratigraphic correlation of grain size and susceptibility data, and the archeological age of cultural layer, the basic age framework of the Holocene profile was determined. The results show that the first flood episode happened in the Jinghe River basin from 4.20 to 4.00 ka and the second flood event occurred from 3.20 to 2.80 ka. These ancient flood events, coincident with the global climate change event, are the responses of the Jinghe Basin climate and hydrological system to global changes.