We investigate the geometry and ventilation of the water masses within bathyal depths (~1,500 to ~2,500 m) of the Southeast Pacific (SEP), inferring the lower depth limit variations of the Antarctic Intermediate Water (AAIW) since ~22 kyr cal. BP. We use three cores collected at the upper limit of the Pacific deep waters, between 41°S and 49°S, and one core at a greater depth within this same water mass, at 46°S. The benthic foraminiferal assemblages and carbon and oxygen isotopes are used to show strong linkages between the timing of the deglacial Southern Ocean upwelling events and changes in the vertical extension and ventilation of the AAIW. In accordance with local/sublocal oxygen reconstructions, we propose at least three states of ventilation‐AAIW vertical extension: (i) the late glacial and the Antarctic Cold Reversal (ACR): AAIW depth‐limit shoals, as its formation zone moves northward; (ii) the deglaciation (excluding the ACR): the [O₂] enrichment of the AAIW and the dominance of benthic species Trifarina angulosa indicate ventilated AAIW, along with a deepening of its lower limit; and (iii) the Holocene: enhanced influence of the Pacific deep water at bathyal depths (1,500–2,500 m) in the SEP north of ~46°S and the circumpolar deep water south of ~46°S.

中文翻译：

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最后一次终止期间东南太平洋中深水区的通风和扩张

我们调查了东南太平洋（SEP）的海床深度（〜1,500至〜2,500 m）内水团的几何形状和通风情况，推断了自22千瓦以来南极中间水（AAIW）的较低深度极限变化。BP。我们使用在太平洋深水上限（41°S和49°S）之间收集的三个岩心，以及在相同水量（46°S）内更深的一个岩心。底栖有孔虫的组合以及碳和氧的同位素被用来显示冰期南大洋上升事件发生的时间与AAIW垂直延伸和通风的变化之间有很强的联系。根据局部/亚局部氧气的重建，我们提出了至少三种通气状态-AAIW垂直延伸：（i）晚冰川和南极逆冷（ACR）：AAIW限深浅滩，其编队区向北移动；（ii）脱冰（不包括ACR）：[O₂ ] AAIW的富集和底栖物种Trifarina angulosa的优势表明通风的AAIW以及其下限的加深；（iii）全新世：太平洋深水在〜46°S以北的SEP和〜46°S以南的绕极深水的深处（1,500–2,500 m）的影响增强。