Geochemical characteristics and geochemical significance of rare earth elements of surface sediments from four typical sections of South China Sea

Seventy-five samples of surface sediments from four representative transects in the South China Sea(SCS, 18°N, 10°N, 6°N; 113°E)were collected for the analysis of rare earth elements (REE) geochemistry.The results showed that the total REE content (∑REE) was relatively low (average 128ppm) in most sediments with high LREE/HREE ratios, low Ce/Ce^*, and moderate Eu/Eu^* values.The spatial distribution of REE was strongly dependent upon the geographical location and depositional environments.There is a positive correlation between Al2O3 and ∑REE, and a negative correlation between CaO and RREE.Terrigenous component and biological carbonates were the two main sources of sediment in the area.Lower Eu/Eu^*, (Gd/Yb)_N and the REE distribution pattern of mast samples indicated that post-Archean felsic rocks are the main source.The relatively low LREE/HREE ratios and high Eu/Eu^* values of the sediments in the eastern sub-basin indicated that a few materials from young volcanic rocks (e.g., rocks in the Luzon arc) was transferred to this area.