南海东北部表层沉积中钙质和硅质微体化石与沉积环境

CALCIUM AND SILICEOUS MICROFOSSIL IN THE SURFACE SEDIMENTS OF THE NORTHEASTERN SOUTH CHINA SEA AND THEIR RELATIONSHIP WITH THE SEDIMENTARY ENVIRONMENT

通过对南海东北部表层沉积中微体化石的丰度和各类比值以及碳酸钙含量的分析,发现易溶类微体化石丰度和比值以及碳酸盐含量随水深的增大而迅速减小,抗溶类微体化石丰度和比值则随水深的增大而迅速增加,各类微体化石丰度和比值以及碳酸钙含量都显示了在3500m附近存在着明显的分界线,应与深海碳酸盐溶解作用有关。浮游有孔虫Q型因子分析结果表明,其优势属种的分布主要受表层水温所控制,但黑潮暖流的南海分支和吕宋岛北端上升流的存在对调查区北部浮游有孔虫的属种分布所起的作用不应忽视。

The abundances and ratios of microfossils as well as carbonate contents in the surface sediment samples from the northeastern part of the South China Sea were quantitatively analyzed in this study. As a result, it is indicated that the abundances and ratios of dissolutionsusceptible microfossils decrease rapidly with the increasing water depth, while those of dissolutionresistant microfossils increase along with the increasing water depth. The Qmode distribution of abundances and ratios of microfossils at the boundary line of 3 500 m should be relative to the strong carbonate dissolutions. The factor analysis of planktonic foraminifera indicates that distribution of dominant genus and species is mainly controlled by the sea surface temperature. However, the branch of the Kuroshio Current and the upwelling off the northern Luzon Island play an important role in the distribution of planktonic foraminifera in the investigated area.