西拉木伦河流域地表沉积物粒度、化学元素分布特征

发布时间：2018-02-23 06:59

本文关键词： 粒度化学元素物源风化过程西拉木伦河内蒙古　出处：《干旱区研究》2017年01期 　论文类型：期刊论文

【摘要】：通过对内蒙古西拉木伦河流域沉积物的采样分析,结果表明:西拉木伦河地表沉积物的粒度组成以63~250μm粒径为主,粒度特征表现出一定的风成特点;化学组成以Si、Al为主,与上陆壳平均化学组成相比,除Si O_2、Co、As Ni、Ba、Ce等元素外,均处于不同程度的亏损;不同河段沉积物粒度参数、化学元素的分布具有一定相似性,且化学元素含量之间存在高度的相关性,均表明其具有相似的的物源;不同河段A-CN-K图解及CIA(化学蚀变指数)揭示了西拉木伦河不同河段地表物质化学风化程度均较低,处于较弱的去Na、Ca阶段。不同河段化学风化程度差异与其局地气候及地貌格局息息相关;不同地貌单元沉积物粒度组成、地球化学过程的递变规律与距河道远近、地貌、植被等因素有关;西拉木伦河平均粒径与一些元素的相关性,说明粒度和化学元素之间存在一定关系。总之,在不同空间尺度上,西拉木伦河地表沉积物理化特征的分异实质上反映了风动力和水动力的差异性分选。该研究对于构建风水两相沉积物综合判别指标等问题有着重要的意义。
[Abstract]:By sampling and analyzing the sediments in the Xilamulun River Basin, Inner Mongolia, the results show that the grain size composition of the surface sediments of the Xilamulun River is mainly 630.250 渭 m, and the grain size characteristics show certain wind characteristics, and the chemical composition is mainly Si-Al. Compared with the average chemical composition of the upper continental crust, all the elements such as SiO2, CoCoAs, NiNiOCe and so on are in different degrees of depletion, and the distribution of chemical elements is similar to the grain size parameters of sediments in different reaches, and the distribution of chemical elements is similar to each other. There was a high correlation between chemical elements content, which indicated that they had similar provenances, and A-CN-K diagrams and CIAs of different reaches revealed that the chemical weathering degree of surface matter in different reaches of Xilamurun River was lower than that in other reaches of Xilamurun River. The chemical weathering degree of different reach is closely related to the local climate and geomorphologic pattern, the grain size composition of different geomorphologic units, the progressive regularity of geochemical process and the geomorphology from the far to near river, geomorphology, etc. The correlation between the average particle size and some elements in the Xilamurun River indicates that there is a certain relationship between the grain size and the chemical elements. In short, on different spatial scales, The difference of physical and chemical characteristics of surface sediments in Ximulun River reflects the difference between wind and hydrodynamics. This study is of great significance for the construction of comprehensive discriminant indexes of geomantic two-phase sediments.
【作者单位】：北京师范大学防沙治沙教育部工程研究中心;北京师范大学地表过程与资源生态国家重点实验室;陕西师范大学旅游与环境学院;
【基金】：国家重大科学研究计划(2013CB956001) 地表过程与资源生态国家重点实验室自由探索项目(2015-ZY-14) 国家自然科学基金项目(41171003,41401006)共同资助
【分类号】：P512.2

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