为揭示白洋淀地区晚更新世末期气候环境变化特征与未来演化趋势,通过综合分析白洋淀南部地区ZK02钻孔中的湖泊沉积物粒度组分特征,并且在测年的基础上,对晚更新世末期(26.9 ka B.P.)以来白洋淀的环境气候变化进行综合分析.结果表明:26.9-10.5 ka B.P.期间,该地区以洪冲积沉积为主,气候处于冰期向间冰期过渡阶段,但总体仍比较干燥;10.5-8.3 ka B.P期间,沉积环境以河流相沉积为主,气候比前一阶段温暖湿润;在8.3 ka B.P.至今期间,该地区沉积环境逐渐以湖相沉积为主,气候以温暖湿润的间冰期气候为主,并于全新世中期(约6.6 ka B.P.)达到晚更新世末期以来气候最温暖湿润的时期,随后于3.2 ka B.P.和1.8 ka B.P.前后发生了两次明显的冷干波动,在地质构造与河流变迁的影响下,白洋淀开始萎缩解体,加之受到人类活动的干扰,最终形成了白洋淀湖泊的现代形态格局.综上所述,受季风演化的影响,华北地区末次冰期环境冷干,早全新世开始转湿,中全新世最湿,晚全新世环境转干.这一湖泊演化模式与东亚夏季风的演化模式相似,对于理解人类活动影响下的未来季风演化模式具有重要的参考价值.
Grain Size Characteristics and Environmental Significance of Sediments in the Southern Baiyangdian Area during the Late Pleistocene
To reveal the characteristics of climate and environmental changes in the Baiyangdian area during the late Pleistocene and their future evolutionary trends,a comprehensive analysis was conducted on the climate dry and wet changes in Baiyangdian since the late Pleistocene(26.9 ka B.P.)by analyzing the grain size characteristics of lake sediment in a borehole in the southern part of Baiyangdian,combined with chronological data.The results show that in the period of 26.9～10.5 ka B.P.,the area mainly tubidity current deposit under deluvial and alluvial function,and the climate is in the recovery process in the post glacial age,but generally dry.In the period of 10.5～8.3 ka B.P.,the depositional environment is mainly fluvial facies deposit,and the climate is warmer and moister than in the previous period.During the period from 8.3 ka B.P.to the present,the dipositional environment has gradually transitioned from fluvial facies deposit to lake facies deposit,and the climate has become mainly warm and moist glacial climate,reached the period of the warmest and moistest climate since the end of the Late Pleistocene epoch in the mid-Holocene(about 6.6 ka B.P.),and then gone through two times of remarkable cold-arid fluctuation around 3.2 ka B.P.and 1.8 ka B.P.Baiyangdian started to shrink and disintegrate under the impact of geological structure and rivers'vicissitude,and finally formed the modern patterns of Baiyangdian Lake,under the interference of human activities.In summary,due to the influence of monsoon evolution,the environment in North China during the last glacial period is cold and dry.It begins to turn wet in the early Holocene,is the wettest in the middle Holocene,and became dry in the late Holocene.This lake evolution model is similar to the evolution model of the East Asian summer monsoon,and has important reference value for understanding the future monsoon evolution model under the influence of human activities.
万方数据
维普
