Foraminiferal assemblage and isotope studies of diatomaceous deposits collected under the subarctic convergence in the North Atlantic

利用北大西洋亚北极辐合带下的晚更新世硅藻沉积，研究了有孔虫组合和氧同位素的地层变化。地表和地下浮游有孔虫（Globigerina quinqueloba和Neogloboquadrina pachyderma sinstral）的氧同位素表明，形成垫的硅藻Thalassiothrix longissima在较冷的地表水条件下极为丰富，而在较暖的地表水条件下则普遍存在。证据表明，硅藻席的沉积与地表水条件密切相关。

Stratigraphic variation in foraminiferal assemblage and oxygen isotope was examined using the late Pleistocene diatomaceous deposits collected under the subarctic convergence in the North Atlantic. Oxygen isotope from surface and subsurface dwelling planktic foraminifers (Globigerina quinqueloba and Neogloboquadrina pachyderma sinistral) revealed that mat-forming diatom, Thalassiothrix longissima, occurred extremely abundant under cooler surface water condition, while it occurred commonly under warmer surface water one. The evidence suggests that deposition of the diatom mats is closely related to the surface water conditions.