2023年12月4日出版的《自然—地球科学》杂志发表了英国伦敦大学学院 Fox, Matthew 团队的一项最新研究成果。该团队的最新研究提出了由景观演化和动力地形决定的南极半岛冰川模式。

研究人员利用反演分析，重建了南极半岛的古地表地形和地表隆起的长波变化，反演分析将局部地形残余物与整个现代水系网络的分支结构同化。研究发现，由于来自地幔的动力支持，南极半岛在构造上上升了 1.5 km。与现代相比，以当前气候及古地形为主题的冰川学模拟显示南极半岛北部的冰面积大大减少，这表明在近海地点确定的冰川作用的开始反映了地形的构造隆起，而不是气候变冷。

然而，研究人员认为，在南极半岛南部低起伏的冰川期前地貌，比现代山地地形支撑了更大的冰量，说明了侵蚀雕刻对冰川模式的影响。

据研究人员介绍，过去冰盖的尺寸提供了古气候的记录，但这取决于冰盖下面的地形，这种地形在地质时间尺度上通过构造隆起和侵蚀下切而演变。更新世时期(2,580 至 11,650 年前)的侵蚀作用使某些地区的冰川面积减少，尽管气候变冷，但其他非气候影响是否影响了冰川地质记录却鲜为人知。南极半岛悠久的冰川历史和低起伏的冰川期地表地貌为研究这个问题提供了一个机会。

附：英文原文

Title: Antarctic Peninsula glaciation patterns set by landscape evolution and dynamic topography

Author: Fox, Matthew, Clinger, Anna, Smith, Adam G. G., Cuffey, Kurt, Shuster, David, Herman, Frederic

Issue&Volume: 2023-12-04

Abstract: The dimensions of past ice sheets provide a record of palaeoclimate but depend on underlying topography, which evolves over geological timescales by tectonic uplift and erosional downcutting. Erosion during the Pleistocene epoch (2,580 to 11.650 thousand years ago) reduced glacier extent in some locations even as climate cooled, but whether other non-climatic influences impacted the glacial–geological record is poorly known. The Antarctic Peninsula provides an opportunity to examine this issue because of its long glacial history and preservation of remnants of a low-relief pre-glacial land surface. Here we reconstructed both palaeo-surface topography and long-wavelength variations of surface uplift for the Antarctic Peninsula by using inverse analysis that assimilates local topographic remnants with the branching structures of entire modern drainage networks. We found that the Antarctic Peninsula rose tectonically by up to 1.5km due to dynamical support from the mantle. Glaciological models using the current climate and our palaeotopography show greatly reduced ice extent in the northern Antarctic Peninsula compared with modern, indicating that the onset of glaciation identified at offshore sites reflects tectonic uplift of the topography rather than climatic cooling. In the southern Antarctic Peninsula, however, we suggest the low-relief pre-glacial landscape supported a considerably greater ice volume than the modern mountainous topography, illustrating the influence of erosional sculpting on glaciation patterns.

DOI: 10.1038/s41561-023-01336-7

Source: https://www.nature.com/articles/s41561-023-01336-7