南海表层沉积物稀土元素的地球化学

REE GEOCHEMISTRY IN SURFACE SEDIMENTS OF SOUTH CHINA SEA

根据来自南海的94个样品,测定了15个稀土元素。分析结果表明,南海沉积物稀土平均含量为152ppm。运用球粒陨石标准化分布模式研究了南海沉积物的稀土元素地球化学,华南沿海广泛分布的中生代中酸性火成岩碎屑是南海表层沉积物稀土的主要来源,中央海盆东南部沉积物有火山物质的混入,属混合型大洋沉积物。

REE geochemistry in the surface sediments of South China Sea has been studied. 94 samples from the South China Sea were determined for 15 rare earth elements by ICP-AES method.The analytical results show that average REE contents are 152 ppm in the surface sediments of South China Sea.The chondrite-normalized REE distribution patterns show a negative Eu anomaly, and distribution curves are negative in the slope for sediments from most sedimentary areas of the South China Sea. But the REE distribution patterns do not show a negative Eu anomaly in sediments from the central basin, which is most distinct in sediments from the southeast central basin. It is considered that the fragments of Mesozoic intermediate-acid igneous rocks widely distributed along the coast of South China are the main source of REE in the surface sediments of the South China Sea. The sediments in the southeast central basin have been reworked by volcanic materials and are oceanic of mixed type.