Scars of tectonism promote ice-sheet nucleation from Hercules Dome into West Antarctica
Scars of tectonism promote ice-sheet nucleation from Hercules Dome into West Antarctica
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DOI：
10.1038/s41561-023-01265-5
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发表时间：
2023-10-12
影响因子：
18.3
通讯作者：
Christianson，Knut
中科院分区：
文献类型：
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作者：
Hoffman，Andrew O.;Holschuh，Nicholas;Christianson，Knut
地质学和河床地形影响冰盖对气候变化的反应。尽管西南极冰盖有能力在其过度加深的内部迅速后退和前进，但人们对东南极高地内部的冰下景观知之甚少，这可能是西南极冰流和冰川的种子。在大力神圆顶，我们使用三维扫描雷达技术来成像大型冰下盆地的上游起源，这些盆地将南极内陆的冰排入南极西部的冰流。雷达成像显示了一个古老的高山景观，有悬挂的支流山谷和大的U形山谷。在谷底，我们的图像通常与温带基底条件和快速冰流相关联的冰下地貌。这些冰下地貌的形成机制与目前缓慢流动的冰根本不一致。区域空气重力表明，这些山谷流入更大的冰下盆地，那里有厚厚的沉积物柱。过去的构造运动可能创造了这些盆地，并促进了冰流从大力神圆顶进入罗斯和菲尔希纳-罗恩部门。这表明，大力士穹丘的景观是由快速流动的冰在过去形成的，当时该地区可能是南极西部冰盖的成核中心。
Geology and bed topography influence how ice sheets respond to climate change. Despite the West Antarctic Ice Sheet’s capacity to retreat and advance quickly over its over-deepened interior, little is known about the subglacial landscape of the East Antarctic elevated interior that probably seeded West Antarctic ice streams and glaciers. At Hercules Dome, we use three-dimensional swath radar technology to image the upstream origin of large subglacial basins that drain ice from the Antarctic interior into West Antarctic ice streams. Radar imaging reveals an ancient, alpine landscape with hanging tributary valleys and large U-shaped valleys. On the valley floors, we image subglacial landforms that are typically associated with temperate basal conditions and fast ice flow. Formation mechanisms for these subglacial landforms are fundamentally inconsistent with the currently slowly flowing ice. Regional aerogravity shows that these valleys feed into larger subglacial basins that host thick sediment columns. Past tectonism probably created these basins and promoted ice flow from Hercules Dome into the Ross and Filchner–Ronne sectors. This suggests that the landscape at Hercules Dome was shaped by fast-flowing ice in the past when the area may have served as or been proximal to a nucleation centre for the West Antarctic Ice Sheet.