Reconstruction of changes in the Weddell Sea sector of the Antarctic Ice Sheet since the Last Glacial Maximum
Reconstruction of changes in the Weddell Sea sector of the Antarctic Ice Sheet since the Last Glacial Maximum
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DOI：
10.1016/j.quascirev.2013.07.020
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发表时间：
2014-09-15
影响因子：
4
通讯作者：
Sugden, David E.
中科院分区：
文献类型：
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作者：
Hillenbrand, Claus-Dieter;Bentley, Michael J.;Sugden, David E.
威德尔海地区是南极底水的主要形成地点之一，也是南极洲大陆冰量的五分之一的出口。在过去的几十年里，对该部门冰川地质记录的研究提供了自末次盛冰期（LGM）以来冰盖范围和冰盖厚度变化的相互矛盾的重建。从威德尔海腹地的岩石中获得的陆地地貌记录和暴露年龄、冰芯的冰盖厚度限制以及近海沉积物的一些放射性碳年代分析表明，在LGM没有明显的冰增厚和局部限制的地线推进。其他海洋地质和地球物理研究得出的结论是，在威德尔海大陆架上绘制的冰下河床、冰下沉积物和被岩心中回收的覆冰过度压实的沉积物，以及从海洋沉积物中获得的少数可用放射性碳年龄与LGM的主要冰盖推进一致。反映地质解释，不同的冰盖模型重建了威德尔海地区相互冲突的LGM冰盖结构。因此，威德尔海部分的冰盖堆积对LGM海平面低水位（约130米）的估计贡献差异很大。在本文中，我们总结和回顾了威德尔海板块过去的冰盖边缘和冰盖高度的地质记录。我们收集了限制前冰盖大小的海洋和陆地年代学数据，从而突出了不同程度的确定性，并提出了两种LGM冰盖配置的备选方案，包括LGM后接地线退缩的时间片重建。此外，我们还讨论了各种重建之间的一致性和不一致性的可能原因，并提出了未来研究的目标。我们研究的目的是为威德尔海地区南极冰盖历史的冰川地质数据集提供两种不同的解释，这些解释可用于测试和改进数值冰盖模型。(C) 2014年作者。Elsevier Ltd.出版。版权所有。
The Weddell Sea sector is one of the main formation sites for Antarctic Bottom Water and an outlet for about one fifth of Antarctica's continental ice volume. Over the last few decades, studies on glacial geological records in this sector have provided conflicting reconstructions of changes in ice-sheet extent and ice-sheet thickness since the Last Glacial Maximum (LGM at ca 23-19 calibrated kiloyears before present, cal ka BP). Terrestrial geomorphological records and exposure ages obtained from rocks in the hinterland of the Weddell Sea, ice-sheet thickness constraints from ice cores and some radiocarbon dates on offshore sediments were interpreted to indicate no significant ice thickening and locally restricted grounding-line advance at the LGM. Other marine geological and geophysical studies concluded that subglacial bedforms mapped on the Weddell Sea continental shelf, subglacial deposits and sediments over-compacted by overriding ice recovered in cores, and the few available radiocarbon ages from marine sediments are consistent with major ice-sheet advance at the LGM. Reflecting the geological interpretations, different ice-sheet models have reconstructed conflicting LGM ice-sheet configurations for the Weddell Sea sector. Consequently, the estimated contributions of ice-sheet build-up in the Weddell Sea sector to the LGM sea-level low-stand of similar to 130 m vary considerably.In this paper, we summarise and review the geological records of past ice-sheet margins and past ice-sheet elevations in the Weddell Sea sector. We compile marine and terrestrial chronological data constraining former ice-sheet size, thereby highlighting different levels of certainty, and present two alternative scenarios of the LGM ice-sheet configuration, including time-slice reconstructions for post-LGM grounding-line retreat. Moreover, we discuss consistencies and possible reasons for inconsistencies between the various reconstructions and propose objectives for future research. The aim of our study is to provide two alternative interpretations of glacial-geological datasets on Antarctic Ice-Sheet History for the Weddell Sea sector, which can be utilised to test and improve numerical ice-sheet models. (C) 2014 The Authors. Published by Elsevier Ltd. All rights reserved.