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本文通过对长江三峡大宁河流域大昌镇张家湾遗址的研究,揭示了本区3000年来的沉积环境变化以及古洪水情况。沉积学研究表明本区这一时期经历了至少三次特大的流域性洪水。磁化率研究表明,汉代之前该区处于稳定的干凉气候,唐宋时期气温变化幅度较大,但有明显的高温期,这与竺可桢关于中国5000年气候变化特征的研究结果类似。结合磁化率的沉积环境的综合分析表明,该区第一次特大古洪水有可能发生在唐宋的高温期,第二次和最近一次特大洪水有可能发生于明清时期和近期。
Based on the study of the Zhangjiawan site in Dachang Town of the Daning River in the Three Gorges of the Yangtze River, this paper reveals the changes of sedimentary environment and the floods in the past 3,000 years. Sedimentology studies show that the region experienced at least three super-large watershed floods during this period. The study of magnetic susceptibility shows that the area was in a stable dry and cool climate before the Han Dynasty, and the temperature in the Tang and Song Dynasties had a wide range of temperature but a marked high temperature period. This is similar to Zhu Kezhen’s research on the characteristics of climate change over the past 5,000 years in China. The comprehensive analysis of the sedimentary environment combined with the susceptibility shows that the first extraordinary flood in this area is likely to occur in the high temperature period of the Tang and Song Dynasties. The second and the latest major flood may occur in the Ming and Qing Dynasties and in the near future.