Abrupt Holocene ice loss due to thinning and ungrounding in the Weddell Sea Embayment
Abrupt Holocene ice loss due to thinning and ungrounding in the Weddell Sea Embayment
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由于威德尔海海湾变薄和不接地导致全新世冰突然流失
DOI：
10.1038/s41561-024-01375-8
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发表时间：
2024
影响因子：
18.3
通讯作者：
Grieman M
中科院分区：
文献类型：
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作者：
Grieman M
接地冰的范围和伦讷冰架的支撑，这提供了对冰流外流的阻力，适度的南极西部冰盖的稳定性。在末次盛冰期，冰盖向前推进，并在威德尔海大陆架断裂处附近搁浅。随后冰盖退缩的时间和冰架支撑和接地线变化的相对作用仍然没有解决。在这里，我们使用的冰芯记录地面冰在Skytrain冰隆约束的时间和速度的早期全新世冰盖撤退。测量的δ 18 O和总空气含量表明，Skytrain Ice Rise的表面海拔在1950年之前的8.2和8.0 kyr之间下降了约450 m（±0.13 kyr）。我们把这种海拔变化归因于该地区冰不接地引起的流量变化引起的动态变薄。冰芯钠浓度表明，在1950年之前，这个未接地的冰架的冰锋从7.7到7.3 kyr后退了大约270 km（±30 km）。这些百年尺度的变化表明，在没有大规模冰架崩解的情况下，由于地面冰的变化，南极西部冰盖的冰量可以多么迅速地消失。我们的研究结果支持和时间限制冰盖模型，表现出快速的冰损失在威德尔海部门在全新世早期。
The extent of grounded ice and buttressing by the Ronne Ice Shelf, which provides resistance to the outflow of ice streams, moderate West Antarctic Ice Sheet stability. During the Last Glacial Maximum, the ice sheet advanced and was grounded near the Weddell Sea continental shelf break. The timing of subsequent ice sheet retreat and the relative roles of ice shelf buttressing and grounding line changes remain unresolved. Here we use an ice core record from grounded ice at Skytrain Ice Rise to constrain the timing and speed of early Holocene ice sheet retreat. Measuredδ18O and total air content suggest that the surface elevation of Skytrain Ice Rise decreased by about 450 m between 8.2 and 8.0 kyr before 1950ce(±0.13 kyr). We attribute this elevation change to dynamic thinning due to flow changes induced by the ungrounding of ice in the area. Ice core sodium concentrations suggest that the ice front of this ungrounded ice shelf then retreated about 270 km (±30 km) from 7.7 to 7.3 kyr before 1950ce. These centennial-scale changes demonstrate how quickly ice mass can be lost from the West Antarctic Ice Sheet due to changes in grounded ice without extensive ice shelf calving. Our findings both support and temporally constrain ice sheet models that exhibit rapid ice loss in the Weddell Sea sector in the early Holocene.