GEOCHEMICAL CHARACTERISTICS OF SURFACE SEDIMENS IN BOHAI STRAIT AND CONTROLLING FACTORS

Based on the grain size data of surface sediments collected at 412 stations and the geochemical data from 123 stations in the Bohai Strait, we discussed in this paper the spatial distribution pattern of elements, elements correlation, element assemblages, sedimentary dynamic environment and sediment transportation mechanism of the surface sediments, aiming at revealing the environmental significance of sediment geochemistry. The results indicate that the major elements of the surface sediments in the study area are predominated by SiO₂ and Al₂O₃. The content of SiO₂ increase and Al₂O₃ decrease gradually with the increase in grain size of sediments. The highest trace element in the surface sediments is Ba. The element enrichment factors of the sediments from the study area also indicate that the distribution of element content is controlled by the grain size of sediments. The results of cluster analysis further suggest that the spatial distribution of elements in the study area could be subdivided into 5 areass, namely, the relict deposits area, the Laotieshan area, the east and west sides of the watercourse, the central area of the Straits and the southern part of the Straits.