Evolution of the subglacial hydrologic system beneath the rapidly decaying Cordilleran Ice Sheet caused by ice-dammed lake drainage: implications for meltwater-induced ice acceleration
Evolution of the subglacial hydrologic system beneath the rapidly decaying Cordilleran Ice Sheet caused by ice-dammed lake drainage: implications for meltwater-induced ice acceleration
复制标题
由冰坝湖排水引起的快速腐烂的科迪勒拉冰盖下冰下水文系统的演变：对融水引起的冰加速的影响
DOI：
10.1016/j.quascirev.2012.07.005
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发表时间：
2012
影响因子：
4
通讯作者：
A. Perkins
中科院分区：
文献类型：
--
作者：
M. Burke;T. Brennand;A. Perkins
南极冰盖（AIS）和格陵兰冰盖（GrIS）陆地终止部分的冰坝湖排水和冰加速之间的正相关性与冰盖衰减的增强有关。然而，在冰盖床的直接测量的缺乏限制了我们的理解冰下排水系统的演变，响应瞬态水输入。我们提出的证据表明，两个融水走廊的前床薄（600米，在末次冰期最大的内部高原的不列颠哥伦比亚省）和快速衰减的科迪勒拉冰盖（CIS）产生冰下排水的冰坝湖和运河（隧道渠道）。地貌，探地雷达（GPR）和电阻率层析成像（ERT）数据揭示了一个简单的事件序列，包括广泛的初始传播（至少2.5公里宽）洪水波（低效率的排水）从冰坝湖，在走廊顶端相对较短的区域（3-24公里），这些区域坍塌成有效的运河（大的（宽达0.25-2.5公里）水道向下切入沉积床，向上切入冰）冰川下游。弗雷泽高原南部的运河形成涉及同步（沿着运河全长）系统的发展，包括溯源侵蚀和水垫塘形成的要素。我们的数据表明，冰坝湖排水下的快速衰减的薄冰块，有一个有效的先行排水网络是不利于大规模的冰加速。这些数据可能有助于更好地评估冰坝湖排水对前动态的作用，以及当代，冰盖。
A positive correlation between ice-dammed lake drainage and ice acceleration at Antarctic Ice Sheets (AIS) and land-terminating sections of the Greenland Ice Sheet (GrIS) has been implicated in enhanced ice sheet decay. However, the paucity of direct measurements at the ice sheet bed restricts our understanding of subglacial drainage system evolution in response to transient water inputs. We present evidence that two meltwater corridors on the former bed of the thin (∼600 m at Last Glacial Maximum over the interior Plateaus of British Columbia) and rapidly decaying Cordilleran Ice Sheet (CIS) were generated subglacially in response to the drainage of an ice-dammed lake and operated as canals (tunnel channels). Geomorphological, ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) data reveal a simple event sequence that includes initial propagation of a broad (at least 2.5 km wide) floodwave (inefficient drainage) from an ice-dammed lake, over relatively short (3–24 km) zones at the corridor heads that collapsed into efficient canals (large (up to 0.25–2.5 km wide) channels incised down into the sediment bed and up into the ice) downglacier. Canal formation on the southern Fraser Plateau involved synchronous (along the full canal length) system development, including elements of headward erosion and plunge pool formation. Our data suggest that ice-dammed lake drainage beneath a rapidly decaying thin ice mass that has an efficient antecedent drainage network is not conducive to large-scale ice acceleration. These data may aid better assessment of the role of ice-dammed lake drainage on the dynamics of former, as well as contemporary, ice sheets.
影响因子：
18.3
作者：
Bartholomew, Ian;Nienow, Peter;Sole, Andrew
通讯作者：
Sole, Andrew