Ice-flow reorganization within the East Antarctic Ice Sheet deep interior
Ice-flow reorganization within the East Antarctic Ice Sheet deep interior
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DOI：
10.1144/sp461.14
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发表时间：
2018-01-01
期刊：
影响因子：
--
通讯作者：
Siegert, M. J.
中科院分区：
文献类型：
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作者：
Beem, L. H.;Cavitte, M. G. P.;Siegert, M. J.
在南极附近，东南极冰盖下方不到10公里处存在一个大型冰下湖，推断其床温为-9℃。利用热力学模型研究了冷床附近存在基础水的明显矛盾。模型结果表明，南极湖正在结冰，目前的地热通量和冰流都无法产生维持该位置基础水所需的热量。我们假设该湖包含在不同的冰动力学配置期间形成的残余水，当时冰滑动产生显着的摩擦热。假设的底部滑动的附加模型显示摩擦加热能够产生填充南极湖所需的热量。过去，通过机载雷达观测冰盖流测量的冰川结构的独立证据更加动态。根据附近钻孔的冰年表，估计冰滑动在 16.8 至 10.7ka 之间停止。这些发现揭示了末次盛冰期后南极洲东部内部的主要冰动力变化，表明目前的内部冰流与全冰川条件下的不同。
Near the South Pole, a large subglacial lake exists beneath the East Antarctic Ice Sheet less than 10 km from where the bed temperature is inferred to be -9 degrees C. A thermodynamic model was used to investigate the apparent contradiction of basal water existing in the vicinity of a cold bed. Model results indicate that South Pole Lake is freezing and that neither present-day geothermal flux nor ice flow is capable of producing the necessary heat to sustain basal water at this location. We hypothesize that the lake comprises relict water formed during a different configuration of ice dynamics when significant frictional heating from ice sliding was available. Additional modelling of assumed basal sliding shows frictional heating was capable of producing the necessary heat to fill South Pole Lake. Independent evidence of englacial structures measured by airborne radar revel ice-sheet flow was more dynamic in the past. Ice sliding is estimated to have ceased between 16.8 and 10.7 ka based on an ice chronology from a nearby borehole. These findings reveal major post-Last Glacial Maximum ice-dynamic change within the interior of East Antarctica, demonstrating that the present interior ice flow is different than that under full glacial conditions.