运城盆地全新世黄土记录的千年尺度气候突变事件  

Millennium scale climate abrupt events recorded in the Holocene loess of the Yuncheng Basin

作　　者：张妤 杨萍果[1] 赵辉 敖红[2] ZHANG Yu;YANG Pingguo;ZHAO Hui;AO Hong(College of Life Sciences,Shanxi Normal University,Taiyuan 030031,Shanxi;State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi'an 710061,Shaanxi;Xi'an Institute of Earth Environment Innovation,Xi'an 710061,Shaanxi)

机构地区：[1]山西师范大学生命科学学院,山西太原030031 [2]中国科学院地球环境研究所,黄土与第四纪地质国家重点实验室,陕西西安710061 [3]西安地球环境创新研究院,陕西西安710061

出　　处：《第四纪研究》2024年第6期1700-1712,共13页Quaternary Sciences

基　　金：国家自然科学基金面上项目(批准号:42074076);国家自然科学基金国际合作与交流项目(批准号:42261144739)共同资助。

摘　　要：揭示全新世期间东亚季风演化历史与动力学过程对预测未来全球气候变化具有重要意义。古气候研究表明全新世气候在百年至千年尺度上存在一系列气候突变事件,然而目前对中国黄土是否具有记录全新世快速气候变化的潜力仍存在争议。在光释光定年基础上,本研究对运城盆地闻喜县全新世黄土剖面中厚6 m的古土壤层(S0)开展了综合岩石磁学和地球化学古气候替代性指标序列分析,揭示了该地区11.98 ka B.P.以来东亚夏季风降雨的演化历史及其对全球气候突变事件的响应。研究结果表明,该剖面的载磁矿物以磁铁矿和磁赤铁矿为主,磁性颗粒的粒径以单畴(SD)和假单畴(PSD)颗粒为主导,并含有少量多畴(MD)颗粒;磁化率和Rb/Sr比值的一致性变化主要反映了受东亚夏季风控制的成土作用变化,而区域季风降雨在11.98~9.4 ka B.P.呈增加趋势,在9.4 ka B.P.之后呈减少趋势,并在约9.4 ka B.P.达到峰值;此外,高分辨率磁化率记录表明在约4 ka B.P.、6 ka B.P.、8 ka B.P.、9 ka B.P.存在4次显著的气候突变事件,它们与Bond冷事件具有良好的对应关系,可能反映了北半球高纬气候突变对运城盆地的季风降雨的影响。Identifying the evolutionary history and dynamics of the East Asian monsoon during the Holocene is important for predicting future global climate change.Paleoclimate studies have shown that the Holocene climate experienced a series of abrupt climate change events on a centennial to millennial scale,however it is still controversial whether the loess in China has the potential to record rapid climate change in the Holocene.In this study,the loess section(110°59'33″~111°37'29″E,35°09'38″~35°34'11″N)in Wenxi County,Yuncheng City,Shanxi Province,China was selected for Holocene hydroclimate reconstruction.The entire section was a compact and blackish Holocene paleosol layer S0,with a thickness of 6 m.After removing the weathered soil on the top surface,300 bulk samples were collected at 2 cm intervals and six optically stimulated luminescence(OSL)samples were collected at 1 m intervals.Those OSL ages were incorporated into a Bayesian age-depth model using Bacon software to establish the chronology,which ranges from 11.98~1.68 ka B.P.In this study,we investigated the Wenxi sequences from the southeastern Chinese Loess Plateau,using multi-parameter rock magnetic investigation(such as magnetic susceptibility,temperature-dependent magnetic susceptibility(χ-T),magnetic hysteresis loops,First-Order-Reversal-Curve(FORC),temperature-dependent isothermal remanent magnetization(IRM),low-temperature cycling of room temperature induced SIRM)and geochemical elements to reveal the evolution of East Asian summer monsoon precipitation and its response to abrupt global climate events since 11.98 ka B.P.in this region.Our results indicate that the main magnetite-bearing minerals are magnetite and maghemite.The particle sizes of the magnetic particles are dominated by single-domain(SD)and pseudo-single-domain(PSD)particles,with a small amount of multi-domain(MD)particles.Results of geochemical elements indicate that the distribution of Ca,Ti,Mn,Fe,Rb and Sr is different,among which Ca and Sr are most significantly affected

关 键 词：全新世 运城盆地 季风降雨 气候突变事件 

分 类 号：P534.632[天文地球—第四纪地质学] P318[天文地球—古生物学与地层学]