RARE EARTH GEOCHEMISTRY OF COASTAL SURFICIAL SEDIMENTS OFF ZHEJIANG AND FUJIAN PROVINCES AND ITS IMPLICATIONS FOR PROVENANCE

151 surface sediment samples taking from the argillaceous deposits off the Zhejiang-Fujian coasts and 71 samples from surrounding rivers have been tested in order to reveal the distribution pattern of grain size, rare earth elements, δEu and δCe, and chondrite-normalized and UCC-normalized REEs. The rare earth composition is compared with those of the surface sediments from the Yangtze River, Oujiang River, and Minjiang River.The F_D discriminating function is adopted taking Ce/La and Sm/Nd as the element pair.The results suggest that the surface sediments in the study area are not formed from a single source, but a mixed source of the Yangtze River, Oujiang River, and Minjiang River.The contribution of the three rivers to the deposition on continental shelf surrounding to the study area is in a decreasing order from the Yangtze River to the Oujiang River and finally to the Minjiang River.The Yangtze River is doubtlessly the major contributor of clastic sediments to the inner shelf. However, the sediment sources of the outer shelf surface sediments are rather complex. It seems that the mixingt of the sediments from the three rivers is more important and pronounced on the outer shelf.