山东章丘黄土粒度指示的粉尘堆积过程及古气候意义  

Dust accumulation processes and palaeoenvironmental significance of loess indicated by grain size in Zhangqiu, Shandong Province

作　　者：孔凡彪 陈海涛[2,3] 徐树建 苗晓东[2] KONG Fanbiao;CHEN Haitao;XU Shujian;MIAO Xiaodong(School of Geography and Environment,Shandong Normal University,Jinan 250014,China;Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection,College of Resources and Environment,Linyi University,Linyi 276000,Shandong,China;College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,Shandong,China)

机构地区：[1]山东师范大学地理与环境学院,济南250014 [2]山东省水土保持与环境保育重点实验室临沂大学资源环境学院,临沂276000 [3]山东科技大学地球科学与工程学院,青岛266590

出　　处：《地理学报》2021年第5期1163-1176,共14页Acta Geographica Sinica

基　　金：国家自然科学基金项目(41977262,41472159)。

摘　　要：山东黄土堆积过程记录了中国东部季风区大气环流的变化信息,对揭示东亚季风变化规律与古气候环境演变具有重要价值。本文采用参数化粒度端元分析方法探讨山东章丘剖面沉积物的沉积特征、沉积动力及其环境意义。结果表明:(1)章丘剖面光释光年代(OSL)介于42.24—0.26 ka之间,为晚更新世以来的沉积物。(2)章丘剖面沉积物粒度组分分为5个端元,EM1代表成壤作用产生和携带搬运的粘土组分;EM2代表高空西风远距离搬运的细粉砂组分;EM3代表以浮尘形式存在的沉降组分;EM4是该剖面的主要粉尘来源,代表地方风系作用下低空悬浮搬运的粉砂组分;EM5代表以尘暴形式近地悬移搬运的砂粒组分。EM5组分含量变化对冬季风强度变化具有较好的指示意义,并记录了晚更新世以来的气候波动事件。(3)根据各端元组分含量、低频磁化率(χlf)、土壤颜色(a^(*))等指标,结合OSL结果,有效指示了晚更新世以来章丘剖面沉积环境的阶段性变化,体现了全球气候环境变化的区域响应,但也存在差异性。The accumulation processes of loess in Shandong Province record atmospheric circulation changes in eastern China, which is significant in revealing the varied characteristics of East Asian monsoons and palaeoenvironmental change. In this study, the parameterized endmember modelling analysis of grain-size distributions is used to discuss the sedimentary characteristics, transport dynamics and environmental significance for a loess section in Zhangqiu, Shandong Province. The results indicated that:(1) The optically stimulated luminescence(OSL) ages of the Zhangqiu section ranged from 0.26 to 42.24 ka, suggesting that sediments have mostly deposited since the late Pleistocene.(2) The grain size components of the sediments in this section were divided into five end members: EM1 represents the mixed clay component of pedogenesis and transported sediment, EM2 represents the fine silt component transported by the high-altitude westerly wind over long distance, EM3 represents material that settles as floating dust, EM4 is the main material source of the profile, which represents the silt component transported by low-altitude suspension under local wind systems,and EM5 represents short-distance suspended materials under dust storm conditions. Change in the EM5 component is a good indicator of winter monsoon intensity change, and has recorded all climate fluctuation events since the late Pleistocene.(3) According to the climatic proxies such as the grain-size end-member content, low frequency magnetic susceptibility(χlf) and chromaticity(a^(*)), combined with the results of OSL, this effectively indicated the stage change and differences of the sedimentary environment in the Zhangqiu section since the late Pleistocene and reflected the regional response to global climate change.

关 键 词：黄土 粒度端元分析 粉尘堆积 环境演变 山东省 

分 类 号：P532[天文地球—古生物学与地层学]