Stable isotope record of foraminifera from ODP Hole 114-704A

Isotopic and sedimentologic data from Ocean Drilling Program hole 704A suggest that isotopic stages 7, 9, and 11 were marked by unusually strong interglacial conditions in surface waters of the southern ocean. During interglacial stages 9 and 11, warm surface waters penetrated far poleward and may have led to destabilization of the West Antarctic Ice Sheet. In contrast, the strongest glacial conditions in surface waters of the subantarctic South Atlantic occurred during oxygen isotopic stage 12. Comparisons of benthic carbon isotopic gradients between sites located in the North Atlantic, southern ocean, and Pacific indicate that the production of upper North Atlantic Deep Water (uNADW) was strongest during stages 7,9, and 11 and weakest during stage 12, These results suggest a possible link between the flux of uNADW and paleoceanographic change in the southern ocean and support the traditional NADW-Antarctic connection whereby increased NADW leads to warming of the southern ocean.取自大洋钻探计划（Ocean Drilling Program）704A钻孔的同位素与沉积学数据显示，南大洋表层水体的同位素阶段7、9与11均呈现出异常强盛的间冰期环境特征。在间冰期阶段9与11期间，暖表层水体向极地方向大规模侵入，可能引发了西南极冰盖（West Antarctic Ice Sheet）的失稳。与之形成对照的是，亚南极南大西洋表层水体的最强冰期环境出现于氧同位素阶段12。对比北大西洋、南大洋与太平洋各站位的底栖碳同位素梯度可知，上层北大西洋深层水（upper North Atlantic Deep Water, uNADW）的生成强度在阶段7、9与11时达到顶峰，而在阶段12时最为微弱。上述结果揭示了上层北大西洋深层水通量与南大洋古海洋学变化之间的潜在关联，并佐证了传统的北大西洋深层水-南极关联假说：即北大西洋深层水通量增加会导致南大洋升温。