Abstract The neodymium isotope composition (eNd) of planktic foraminifera and the relative abundances and δ13C of the benthic foraminiferal species C. wuellerstorfi from two gravity cores, retrieved from the western margin of South Africa, provide a late Quaternary (MIS 6 to MIS 1) record of the variations in North Atlantic Deep Water (NADW) and Southern Component Water (SCW). The eNd records from cores at water depths of 3522 m and 3631 m reveal a strong influence of SCW (Lower Circumpolar Deep Water (LCDW) and Antarctic Bottom Water (AABW)) during the peak glacial periods of MIS 6 (eNd = −8.75 to −7.35) and MIS 2 (eNd = −8.44 to −7.27). The strength of the SCW influence decreases while that of the NADW increases during glacial terminations (GT) II (eNd = −10.61 to −9.99) and GT I (eNd = −10.75 to −9.67). More radiogenic eNd values along the flow path of NADW are interpreted to indicate the weakening of NADW penetration southward, as a result of decreasing deep water formation in the North Atlantic during peak glacial periods. The relative abundance and δ13C of C. wuellerstorfi are greater during glacial terminations and interglacials than during peak glacial periods, which is consistent with the less radiogenic eNd values following GT II and GT I. These results suggest that C. wuellerstorfi abundances can be a useful indicator of deep water masses when combined with eNd and δ13C records.

中文翻译：

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南非西部边缘深水团的变化，跨越最后两个冰川终点

摘要 浮游有孔虫的钕同位素组成 (eNd) 和底栖有孔虫物种 C. wuellerstorfi 的相对丰度和 δ13C 来自从南非西部边缘取回的两个重力核心，提供了晚第四纪 (MIS 6 至 MIS 1)北大西洋深水 (NADW) 和南部成分水 (SCW) 变化的记录。来自 3522 m 和 3631 m 水深岩心的 eNd 记录揭示了 SCW（下环极深水 (LCDW) 和南极底水 (AABW)）在 MIS 6 冰期高峰期（eNd = -8.75 至-7.35) 和 MIS 2 (eNd = -8.44 到 -7.27)。在冰川终止 (GT) II (eNd = -10.61 至 -9.99) 和 GT I (eNd = -10.75 至 -9.67) 期间，SCW 影响的强度降低而 NADW 的强度增加。沿 NADW 流动路径的更多放射成因 eNd 值被解释为表明 NADW 向南渗透的减弱，这是由于在冰川高峰期北大西洋深水形成减少的结果。C. wuellerstorfi 的相对丰度和 δ13C 在冰期结束和间冰期比在冰期高峰期更大，这与 GT II 和 GT I 之后放射成因的 eNd 值较低是一致的。这些结果表明 C. wuellerstorfi 丰度可能是有用的结合 eNd 和 δ13C 记录时的深水团指标。