唐宋时期洛阳城洪水事件的地层沉积记录

Sedimentary Record of Historical Flood Events through Tang and Song Dynasty in Luoyang City

通过对隋唐洛阳城定鼎门遗址附近沉积剖面分段采样,并进行粒度和常量元素分析,探讨唐宋时期沉积剖面的成因以及洛阳城洪水事件。粒度组分、概率累积曲线以及频率分布曲线表明,第4,6,7层有3次洪水灾害事件发生;SiO2,Al2O3和Fe2O3等常量元素含量分析结果表明石英、高岭土以及磁性矿物发生迁移,反映沉积环境的改变;第6,7层底部样品中石英增多,高岭土以及磁性矿物减少,印证了粒度分析结果所反映的水灾记录。综合分析表明,在盛唐时期和中唐时期发生过两次较大规模的水灾事件,北宋时期发生过一次较为严重的漫洪堆积过程。研究结果与历史文献的记录基本吻合。

DDM profile lies outside the south gate （Dingding Gate） of Luoyang City （capital as Sui and Tang Dynasty）, Luoyang Basin, Henan, China. Based on measurement and analysis of grain size, major element contents, the authors investigate sedimentary process of the profile and the historical flood events from Tang to North Song Dynasty in Luoyang. Grain size compose, the cumulative probability and frequency distribution curve indicate that there are three flood events in section 4, 6, 7; the major element contents result of SiO2, Al2O3, Fe2O3 percentage changes reflects the migration of quartz, kaolin, and magnetic minerals and environment changes; the increase of quartz and decrease of kaolin and magnetic minerals in the bottom of section 6 and 7 prove the historical flood events reflected by the result of grain size analysis. Comprehensive analysis shows that there are two large-scale floods in the early and middle Tang Dynasty; there is a more serious sheet flood deposits process in North Song Dynasty. The sedimentary record is very consistent with historical documents.