During the last interglaciation (LIG; ∼129–116 ka), global mean sea level (GMSL) was 6–9 m above present. However, the source, or sources, of the higher-than-present sea level are only partially confirmed with far fewer geologic constraints than GMSL itself. Because of modest LIG Greenland Ice-Sheet retreat that raised sea level by < 2.5 m, Antarctic ice sheets are hypothesized to have contributed significantly to the LIG GMSL highstand, but direct evidence is limited. Here we infer ice-sheet presence or absence on West Antarctica and the Antarctic Peninsula using sediment geochemistry in the Bellingshausen Sea at Ocean Drilling Program (ODP) Site 1096. In particular, a combination of Sr-Nd-Pb isotopes and trace-element ratios allows differentiation between silt sourced from West Antarctica and the Antarctic Peninsula. From the Holocene (<11.7 ka) back through Marine Isotope Stage (MIS) 5d (∼116 ka), we find in ∼50% of our samples glacially eroded silt sourced from under the West Antarctic Ice Sheet that was transported to the Bellingshausen Sea in the Antarctic Circumpolar Current, in addition to silt sourced from under the proximal Antarctic Peninsula Ice Sheet. However, West Antarctic-sourced silt is absent during the LIG (MIS 5e) when only Antarctic Peninsula-sourced silt was deposited at ODP Site 1096. This lack of West Antarctic-sourced silt is consistent with the two ice-core constraints on West Antarctic Ice Sheet LIG size, which combined with our record point towards the absence of the West Antarctic Ice Sheet during the LIG. We therefore provide the first marine-based sedimentary evidence that supports West Antarctic Ice-Sheet absence during the LIG.

在最后一次冰期（LIG；〜129–116 ka）期间，全球平均海平面（GMSL）比目前高6–9 m。但是，仅部分证实了高于当前海平面的一个或多个源具有比GMSL本身少得多的地质约束。由于LIG格陵兰冰雪场的适度撤退使海平面升高了<2.5 m，因此假设南极冰盖对LIG GMSL的高水位起了重要作用，但直接证据有限。在这里，我们使用海洋钻探计划（ODP）站点1096的贝灵斯豪森海中的沉积物地球化学来推断南极西部和南极半岛冰盖的存在与否。特别是Sr-Nd-Pb同位素与微量元素比率的组合可以区分来自南极西部的泥沙和南极半岛的泥沙。来自全新世（<11。7 ka）到海洋同位素阶段（MIS）5d（〜116 ka），我们在大约50％的样本中发现了来自南极西部冰盖下方的冰川侵蚀粉砂，该粉砂在南极极地流中被输送到贝灵斯豪森海，以及来自南极半岛冰盖近端的淤泥。但是，在LIG（MIS 5e）期间，只有南极半岛淤泥沉积在ODP站点1096时，才没有南极淤泥。这种南极淤泥的缺乏与南极西部的两个冰芯约束相一致。 LIG的冰盖大小，再加上我们在LIG期间缺少西南极冰盖的记录点。因此，我们提供了LIG期间支持西南极冰层缺失的首个海洋沉积证据。