雅鲁藏布江表层沉积物地球化学元素研究

雅鲁藏布江流域还没有大的工业污染源,仍然属于自然河流.对雅鲁藏布江16个表层沉积样品的全样、小于20μm 和小于63μm 粒级的32种元素含量进行了测定,并分析了与人类活动密切相关的元素 Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Cd 和 Pb 的含量分布特征,以及这些元素含量与粒径之间的关系.结果表明,多数元素(Cs 除外)与西藏土壤元素背景值相差不大, B、Cr、Ni、As 和 Cs 含量高于中国陆壳元素丰度值,但这些元素主要来源于该流域富含这些元素的页岩、片岩和千枚岩等母岩.由于相似的地球化学行为,沉积物中 Cr、Mn、Fe、Co、Ni、Cu、Zn 之间显著正相关;除 Pb、As 外,一些元素(如 Zn、Ni)与沉积物的粒径显著负相关

The geochemical characteristics of sediments of the Yarlung Zangbo River

The Yarlung Zangbo Basin belongs to natural river without industrial pollution. Sixteen surface sediment samples were collected from this river and 32 elements were analyzed. The objectives of this study are to identify the contents of these elements, especially for elements that are closely connected with anthropogenic activities such as Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb, and to investigate relationships between these elements and the mean grain size. The results show that contents of most elements, except Cs of the Yarlung Zangbo bulk sediments, are similar to those of Tibetan soils. Meanwhile, concentrations of B, Cr, Ni, As and Cs are higher than those of China＇s Continental Crust Concentrations. These elements mainly derived from parent rocks such as shale, schist and phyllite of the Yarlung Zangbo basin. Significant correlations are revealed among Cr, Ni, Mn, Fe, Co, Cu and Zn. Additionally, some elements （e.g. Zn, Ni） show significant negative correlation with the mean grain size of sediments.