GEOCHEMISTRY OF MAJOR ELEMENTS IN THE SURFACE SEDIMENTS OF THE OFFSHORE AREA OF SHANDONG PENINSULA AND ITS GEOLOGICAL IMPLICATIONS

In this study,a total of 274 surface sediments from the offshore area of Shandong Peninsula were collected and analyzed for grain-size,total organic carbon(TOC),and major elementss.Results show that SiO2 is the highest major element,followed by Al2O3 as the second.These two major elements make up 77.8% of the total major elements.The composition of major elements depends upon the type of sediment or grain-size.SiO2 is usually enriched in the coarse-grained sediments,whereas Al2O3、Fe2O3、MgO、MnO、P2O5 and K2O are relatively concentrated in fine-grained sediments.However,Na2O and TiO2 are independent from sediment types.The results of correlation and R-factor analysis suggested that the distribution of major element in the surface sediments from the offshore area of Shandong Peninsula can be classified to three groups.The first group consists of SiO2、Al2O3、Fe2O3、MgO、K2O、TiO2、P2O5、TOC,the second includes CaO and CaCO3,and Na2O and MnO belong to the last groups.These three groups may probably represent terrigenous,marine biogenous and marine authigenic sediments respectively.The chemical weathering index of the surface sediments varies from 50-65,depending upon their provenance.The CIA and TiO2/Al2O3 values suggest that the Huanghe sediments are mainly deposited along the offshore area of Shandong Peninsula,controlled by the coastal currents and the sea bottom geomorphology.