中原地区渑池盆地末次冰消期以来的气候与环境变化  

Climate and environmental changes since the last deglaciation period in the Mianchi Basin from Central Plains of China

作　　者：李洪彬 冯兆东 翟秋敏[1,2] 惠争闯 李开封 石天宇 陈亮 刘畅[1,2] 张样洋 Hongbin Li;Zhaodong Feng;Qiumin Zhai;Zhengchuang Hui;Kaifeng Li;Tianyu Shi;Liang Chen;Chang Liu;Yangyang Zhang(College of Geography and Environmental Science,Henan University,Kaifeng 475004,China;Key Laboratory of Earth System Observation and Simulation of Henan Province,Kaifeng 475004,China)

机构地区：[1]河南大学地理与环境学院,开封475004 [2]河南省地球系统观测与模拟重点实验室,开封475004

出　　处：《科学通报》2023年第10期1230-1246,共17页Chinese Science Bulletin

基　　金：国家重点研发计划(2020YFC1521605);河南大学地理与环境学院优秀青年人才培育项目和河南大学黄河文化遗产实验室资助。

摘　　要：为进一步理解和探究末次冰消期以来东亚季风变化的时空特征,特别是全新世东亚季风的进退模式,在AMS14C年代的支持下,基于渑池湖相-湿地剖面的孢粉和沉积学指标(粒度、碳酸钙和总有机碳)的分析资料,重建了渑池盆地18.7 cal ka BP(ka BP表示距今千年)以来的气候与环境变化历史.重建结果表明:18.7~14.8 cal ka BP是草原环境下的黄土堆积时段.14.8~6.7 cal ka BP为湖泊存在时段,此时段是一个森林扩展和支持水域及湿地也扩展的时期.6.7~1.2 cal ka BP为湿地时段.此阶段的孢粉经历了3个亚阶段的变化,第一亚阶段(6.7~5.0 cal ka BP):草本花粉显著增加;第二亚阶段(5.0~2.8 cal ka BP):木本花粉显著增加;第三亚阶段(2.8~1.2 cal ka BP):草本花粉显著增加.基于木本花粉百分比和禾本科/(蒿属+藜科)比值重建的湿度序列显示,渑池盆地早全新世较为湿润(10~8 cal ka BP),中全新世前半段(8~5 cal ka BP)最为干旱,中全新世后半段(5~2.8 cal ka BP)最为湿润,晚全新世(2.8~1.2 cal ka BP)较为干旱.本文将中原地区的全新世湿度序列(即MC-1)与以北(中国北方)和以南(长江中下游地区)的全新世湿度序列进行了比较.比较结果显示:中原地区全新世最干旱时段发生在8.0~5.0 cal ka BP,中国北方全新世最湿润期的时段发生在7.8~5.0 cal ka BP.二者均很好地对应于厄尔尼诺-南方涛动(El Ni?o-southern oscillation,ENSO)强度的低值阶段(8.0~5.0 cal ka BP).长江中下游地区全新世干旱期时段(7.0~3.0 cal ka BP)与ENSO强度的低值阶段也大致相对应.控制东亚季风影响下的中国东部全新世湿度空间格局的主要机制是ENSO状态以及由ENSO调控的西太平洋副热带高压(West Pacific subtropical high,WPSH)的南北向移动.介于长江中下游地区和中国北方之间的中原地区的全新世湿度状况似乎在二者之间摆动:有时候中原地区与长江中下游地区一起变化(如7.0~3.0 cal ka BP时段),有�The last deglacial(18.0–11.5 cal ka BP)and the Holocene(11.5 cal ka BP to the present)have long been regarded as“the most important stages of the Quaternary Period”by the global change research communities.The importance of the last deglacial lies in the fact that it was the most recent geological warming,and elevating our understanding of the warming may thus be helpful in prescribing the future warming scenarios.The importance of the Holocene lies in the fact the projected future warming is occurring under the climatic boundary conditions that are the natural extensions of the Holocene ones.In order to depict the spatiotemporal variations in the strength of East Asian Summer Monsoon(EASM)since the last deglacial with a focus on the Holocene dynamic patterns of EASM,we analyzed pollen assemblages and sedimentological indicators(Grain size,CaCO3 and TOC)of a lacustrine-wetland section in the Mianchi Basin(namely MC-1 section)and reconstructed the histories of bioclimate evolution and environmental change since~18.7 cal ka BP.The reconstruction results show that 18.7–14.8 cal ka BP was a loess accumulation period under a steppe environment,and no water environment(lake or wetland)was formed in the Mianchi Basin at that time.11.4–6.7 cal ka BP was the period of lacustrine deposition,and the upward increasing trend in the content of Concentricystes suggests that the water extent was gradually increasing during this period.6.7–1.2 cal ka BP was a wetland-dominating period that was also featured by significantly lowered content in Concentricystes and significantly elevated contents in Cyperaceae,Typha and Selaginella.This period can be palynologically divided into three intervals:the first interval(6.7–5.0 cal ka BP),herbaceous pollen increased significantly;the second interval(5.0–2.8 cal ka BP),tree pollen increased significantly;the third interval(2.8–1.2 cal ka BP):herbaceous pollen increased significantly.It should be particularly noted that although 2.8–1.2 cal ka BP belonged to the wetland-d

关 键 词：渑池盆地 孢粉 全新世 东亚季风 厄尔尼诺-南方涛动 

分 类 号：P532[天文地球—古生物学与地层学]