Benthic foraminiferal communities at DSDP Sites 94-609 to 94-611

Benthic foraminiferal assemblages from northeast Atlantic DSDP Sites 609, 610, and 611 have been interpreted with reference to modern assemblages known to be linked with the overlying bottom-water masses. It is shown that the water masses in the late Miocene to Pleistocene were similar to those of today. The distribution of the water masses changed with time, however. Antarctic Bottom Water ("AABW"), which at present is restricted to the area south of the Azores, reached as far north as the Gibbs Fracture Zone in the early Pliocene. Increased production of North Atlantic Deep Water in the late Pliocene displaced the AABW to the south

针对东北大西洋深海钻探计划（Deep Sea Drilling Project, DSDP）609、610及611站位的底栖有孔虫组合，研究人员结合已知与上覆底层水团相关联的现代底栖有孔虫组合开展了解译工作。研究表明，晚中新世至更新世时期的底层水团与现今底层水团特征相近，但水团的分布状况随时间发生了演变。当前仅局限于亚速尔群岛以南海域的南极底层水（Antarctic Bottom Water, AABW），在早上新世时期曾向北延伸至吉布斯断裂带。上新世晚期北大西洋深层水（North Atlantic Deep Water, NADW）的生成量增加，促使南极底层水向南发生了位移。