Evidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation.
Evidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation.
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DOI：
10.1038/ncomms10365
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发表时间：
2016-01-18
影响因子：
16.6
通讯作者：
Semiletov I
中科院分区：
文献类型：
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作者：
Jakobsson M;Nilsson J;Anderson L;Backman J;Björk G;Cronin TM;Kirchner N;Koshurnikov A;Mayer L;Noormets R;O'Regan M;Stranne C;Ananiev R;Barrientos Macho N;Cherniykh D;Coxall H;Eriksson B;Flodén T;Gemery L;Gustafsson Ö;Jerram K;Johansson C;Khortov A;Mohammad R;Semiletov I
大约半个世纪前就有人提出了一个假设，即在冰川高峰期，整个北冰洋都有一个1公里厚的冰架。漂浮的冰架在消失后几乎没有保留直接的痕迹，这使得重建变得困难。然而，冰架的海底印记应该存在于冰沿其流动路径沿着的地方。在这里，我们提出了新的证据，冰架接地测深高点在北冰洋中部，复活的概念，冰架延伸到整个北冰洋中部至少在一个以前的冰河时代。新的和以前绘制的冰川地貌一起揭示了一个空间连贯的流动，在某些地区>1公里厚，中央北冰洋冰架的海洋同位素阶段6（140万年）。水深高点可能是冰架发展的关键，因为它是形成稳定冰脊的固定点，从而提供了足够的背应力，使冰架增厚。 在20世纪70年代，人们提出了在冰川高峰期泛北冰洋冰架的发展，由于缺乏证据，这一想法一直存在争议。在这里，作者提出的地球物理测绘数据支持存在这样的冰架在倒数第二次冰期的高峰期140-160 ka。
The hypothesis of a km-thick ice shelf covering the entire Arctic Ocean during peak glacial conditions was proposed nearly half a century ago. Floating ice shelves preserve few direct traces after their disappearance, making reconstructions difficult. Seafloor imprints of ice shelves should, however, exist where ice grounded along their flow paths. Here we present new evidence of ice-shelf groundings on bathymetric highs in the central Arctic Ocean, resurrecting the concept of an ice shelf extending over the entire central Arctic Ocean during at least one previous ice age. New and previously mapped glacial landforms together reveal flow of a spatially coherent, in some regions >1-km thick, central Arctic Ocean ice shelf dated to marine isotope stage 6 (∼140 ka). Bathymetric highs were likely critical in the ice-shelf development by acting as pinning points where stabilizing ice rises formed, thereby providing sufficient back stress to allow ice shelf thickening. The development of pan-Arctic Ocean ice shelves during peak glacials was proposed in the 1970s, an idea that has been disputed due to lack of evidence. Here, the authors present geophysical mapping data supporting the presence of such an ice shelf during the peak of the penultimate glaciation ∼140–160 ka.