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文中基于详细的野外考察,在洛阳盆地汉魏故城遗址邻近河岸选择了YWC剖面,对剖面进行了磁化率、粒度和>0.1mm粒级百分含量等环境代用指标的室内实验分析和测定。通过野外沉积特征识别、室内粒度分析,准确判定了YWC剖面中洛河古洪水平流沉积层,发现YWC剖面记录了10次晚全新世特大洪水事件。YWC剖面中出现多个“古洪水平流沉积层-风吹沙层”互层,其中的平流沉积层为古洪水平流沉积物,风吹沙层则是洪水间歇期当地盛行的东北风搬运的河床沙在阶地上堆积的产物。平流沉积层与风吹沙层在YWC剖面的多次交替,反映出洛阳盆地晚全新世时期气候、环境系统的剧烈波动和恶化,东北季风强盛和古洪水事件的频繁发生。
Based on the detailed field investigation, the YWC profile was selected near the bank of the ancient city of Han and Wei in Luoyang basin, and the indoor experiment analysis and determination of environmental proxy indexes such as magnetic susceptibility, particle size and particle size percentage> 0.1mm were carried out. Through the analysis of the sedimentary features in the field and the indoor particle size analysis, the horizontal flow sediments of the Lo River in the YWC section were accurately determined. It was found that the YWC profile recorded 10 late Holocene catastrophic events. The YWC profile shows a number of “horizontal flood flow sediments - wind and sand layers ” interbedded layers, of which the advection sediments are paleoclimate sediments and the wind-blown sand layers are northeasterly winds The product of riverbed sand stacked on terraces. Multiple alternations of advection sediments and wind-blown sand layers in the YWC profile reflect the frequent fluctuations of climate and environmental systems in the Luoyang basin during the Late Holocene, the strong northeast monsoon and ancient flood events.