边缘海与大洋第三纪钙质超微化石群比较研究

通过南海北部大陆架某钻孔(Y6)和西太平洋DSDP 296钻孔第三纪地层中超微化石群进行直接对比,同时收集Lohmann和Carlson(1981)对17个太平洋深海钻孔、Ellis(1973)对DSDP31航次7个钻孔超微化石研究资料进行间接对比,发现边缘海和大洋第三纪钙质超微化石群的分布有着不同特点,表现在;(1)边缘海陆架地区化石丰度低,而大洋丰度高,是边缘海陆架区的37倍。(2)边缘海陆架地区化石分异度低。(3)小型钙质超微化石在边缘海陆架地区含量丰富,而大个体类型在大洋中含量高。(4)Sphenolithus和 Helicosphaera在边缘海陆架地区多,而 Discoaster在大洋中含量高,几近前者的15倍。文中最后对造成这种差别的原因进行了讨论。

A COMPARATIVE STUDY OF TERTIARY CALCAREOUS NANNOFOSSILS FROM MARGINAL SEA AND OPEN OCEAN

Through correlation of nannofossils from one well in the northern continental shelf ofthe South China Sea and DSDP site 296, and by comparison of this study with Lohmann andCarlson (1981) and Ellis (1973) on Tertiary nannofossils distribution of the Pacific region,the author has discovered that the nannofossils in the Tertiary marine sequence in the shelfregion of the marginal sea differ from those in the open ocean, mainly in the lower abundanceand diversity, higher amounts of small-sized nannofossil, higher content of Sphenolithus andHelicosphaera, and lower content of Discoaster. The causes of these differences are also dis-cussed.