河套平原湖泊陈普海子沉积物粒度与元素分析  

The characteristics of grain size and elements from Lake Chenpu sediment in the Hetao Plain

作　　者：汪敬忠 朱迟[3] 兰波 李霄 刘卓 WANG Jing-zhong;ZHU Chi;LAN Bo;LI Xiao;LIU Zhuo(Experiment and Practice Teaching Center, Heibei GEO University, Shijiazhuang 050031,China;State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences,Xi’an 710061, China;Jiangsu Provincial Academy of Environmental Science, Jiangsu Provincial Key Lab of Environmental Engineering, Nanjing 210036, China;College of Environmental and Chemical Engineering, Chongqing Three Gorges University,Chongqing 404000, China)

机构地区：[1]河北地质大学实验实践教学中心,河北石家庄050031 [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]江苏省环境科学研究院江苏省环境工程重点实验室,江苏南京210036 [4]重庆三峡学院环境与化学工程学院,重庆404000

出　　处：《中国环境科学》2019年第1期358-365,共8页China Environmental Science

基　　金：国家自然科学基金资助项目(41702165);黄土与第四纪地质国家重点实验室开放基金资助项目(No.SKLLQG1717);河北省自然科学基金资助项目(D2018403115);河北省水利科技计划项目(2017-61)

摘　　要：通过对河套地区不同类型沉积物进行粒度和元素分析,根据区域陈普海子沉积岩芯的年代和环境代用指标结果,借助于判别分析技术,结合历史文献资料,揭示区域近300a来两个典型时段的环境变化.结果表明,约1850a受黄河河道变迁引起的洪水活动影响,陈普海子岩芯55～50cm(CP1)沉积物表现为灰黄色黏土层,其粒度参数、分布曲线与黄河岸边缓流沉积物相似,两者的中值粒径和众数数值分别为3.8, 7.7μm和4.4, 5.0μm,元素及其比值K/Ti、Al/Ti和K/Sr(数值分别为7.1、21.5、102.7和6.2、20.7、87.8)的得分散点分布在判别得分散点图的同一区域,与其它类型沉积物的分布区域明显分离,元素比值K/Ti、Al/Ti和K/Sr可作为湖泊沉积指示洪水活动的环境代用指标;自1995年以来,由于区域人类活动,沙荒土地大规模开垦,致使风沙活动增强,岩芯15cm以上(CP2)沉积物粒度参数、分布曲线与风积物相似,两者的中值粒径和众数数值分别为20.1, 19.6μm和41.6, 45.7μm,元素的得分散点分布在判别得分散点图的同一区域,研究结果与文献记录具有较好的一致性.In this paper,grain size and element from different sediments in the Hetao Basin were analyzed,based on the results of age and environmental indicators from Lake Chenpu sediment,by means of canonical discriminant analysis technology,and combined with historical and literature materials,environmental changes were revealed during two typical periods in recent 300years.Because of the flood activities from the migration of the Yellow River channel in about 1850AD,the grain size characteristics of the sediments at 55~50cm of Lake Chenpu sediment(CP1),which displayed grey-yellow clay layer,were closed related to the slow-flow sediment along the Yellow River bank,their median diameter and mode value were 3.8μm,7.7μm and 4.4μm,5.0μm respectively,and the values of the elements and their ratios(including K/Ti,Al/Ti and K/Sr)were 7.1,21.5,102.7 and 6.2、20.7、87.8 respectively,and their scattered points were also distributed in the same area in the canonical discriminant score scatter plot,which was separated from the distribution areas of other types of sediments,and the element ratios(including K/Ti Al/Ti and K/Sr)could be taken as environmental proxy indicators for the flood activity from the lake sediments.Since 1995,due to the large-scale reclamation of sandy land under human activities in this region,wind-sand activities enhancing,the grain size characteristics of the sediments at the top of 15cm(CP2)were similar to the aeolian sediment,their median diameter and mode value were 20.1μm,19.6μm and 41.6μm,45.7μm respectively,and their elements scattered points were also distributed in the same area,and the study results were in good agreement with the literature records.

关 键 词：河套平原 沉积物 粒度 元素 判别分析 环境变化 

分 类 号：X142[环境科学与工程—环境科学]