论文部分内容阅读
通过对平凉大寨全新世黄土剖面的粒度、磁化率、地球化学参数及年代学的综合分析,着重探讨了本区早、中全新世千百年尺度的气候变化及不稳定性等演变特征。研究表明:平凉大寨地区早全新世升温阶段(11.5~9.2KaB.P.)出现了YD事件,反映了升温过程中短暂性气候逆转;中全新世大暖期(9.2~3.5KaB.P.)存在一个近两千年的冷干气候恶化阶段(6.5~4.5KaB.P.),该冷干气候恶化期存在两个数百年尺度的极度冷干气候事件,其气候环境条件恶化程度接近于晚冰期。同时,该地区中全新世气候变化也存在周期约1.5ka的暖湿与冷干气候旋回。
Based on the comprehensive analysis of the grain size, magnetic susceptibility, geochemical parameters and chronology of the Holocene loess section in Dazhai, Pingliang, the evolution characteristics of climatic changes and instabilities at the Cenozoic and Cenozoic scales in the area are mainly discussed. The results show that the YD event occurred during the Early Holocene warm-up period (11.5 ~ 9.2KaB.P.) In Dazhai, Pingliang, indicating a transient climate reversal during the warming process. During the Mid-Holocene (9.2 ~ 3.5KaB.P.), ) There is a cold-dry climatic deterioration phase (6.5 ~ 4.5KaB.P.) For nearly two thousand years. There are two extremely cold and dry climatic events with several hundred-year scales in the cold-dry climatic deterioration period, and the deterioration of climatic and environmental conditions is close to Late glacial. Meanwhile, the warm-wet and cold-dry climatic cycles with a period of about 1.5 ka also exist in the Holocene climate change in the area.