Trace element geochemistry of the surface sediments in the Liujiaxia Reservoir,Gansu

The concentration,correlation,spatial distribution,controlling factor and source of 25 trace elements in the surface sediments from the Liujiaxia Reservoir,Gansu are analyzed by using the multivariate statistical method. The mean contents of the elements Sr,Zn,Zr and Ba are higher than 170 μg/g,while the values of the elements Cd,Mo and Tl are lower than 1 μg/g in the surface sediments from the Liujiaxia Reservoir. The values of other analyzed elements lie within the range of 2.01-104.34 μg/g. Evident correlation and similar distribution exist among the elements Cu,V,Co,Cr,Ni,Rb,Li,Cd,Be,Pb,Sc,As,Ga,Nb,Sn,Cs,Tl,Th and Al₂O₃. Factor analysis shows that the trace elements in the Liujiaxia Reservoir are divided into three main sources in the following. The distribution of the first component elements is controlled by the weathering and erosion of the natural minerals and rocks,and their contribution rate is 63.20%. The Zr and Ba distribution of the second component elements are mainly affected by the migration and transformation of the elements in the fluvial sediments,and their contribution rate is 12.51%. The Sr distribution of the third component elements is mainly controlled by the biogenic origin,and their contribution rate is 9.76%. In addition,the contents of the elements Zn and As in the heavy metallic elements in the study area are much higher than the average values of the global shales,which is worth further study in the future.