Are drumlins a product of a thermo-mechanical instability?
Are drumlins a product of a thermo-mechanical instability?
复制标题
鼓膜是热机械不稳定性的产物吗？
DOI：
10.1016/j.yqres.2012.12.002
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发表时间：
2013
影响因子：
2.3
通讯作者：
A. Medford
中科院分区：
文献类型：
--
作者：
R. Hooke;A. Medford
在众多的关于鼓林起源的理论中，没有一个被广泛接受。然而，似乎很明显，这涉及到某种形式的积极反馈过程。在某些情况下，扰动会被放大。在这里，我们认为，斑块地区的冻结床提供了初始扰动。这种冻结的斑块可能出现在局部地区，其下方的材料导热性较低，或在轻微的地形高点。冰冻区域产生的拖曳力使冰流偏转到背风处，并随着冰流移动的，直到融化区域被侵蚀。能量平衡是这样的，这仍然可能重新冻结，要么产生地形扰动或放大现有的一个。由此产生的地形，然后偏转更多的地热远离发展中的山丘，并进入相邻的槽，导致正反馈。一旦热扰动超过临界（尽管尚未定义）水平，融化可能会使冰与床分离，防止冰从解冻区域进一步夹带，从而限制鼓状物的高度和长度。
Of numerous theories of drumlin genesis, none has been widely accepted. It seems evident, however, that some form of positive feedback process is involved. Under certain circumstances perturbations are amplified. Herein we suggest that patchy areas of frozen bed provide the initial perturbation. Such frozen patches may occur in local areas underlain by material of lower thermal conductivity or on slight topographic highs. Drag exerted by the frozen patch deflects ice flow into its lee, dragging with it mobile till eroded from the thawed area. The energy balance is such that this till likely refreezes, either producing a topographic perturbation or amplifying an existing one. The resulting topography then deflects more of the geothermal heat away from the developing hill and into the adjacent trough, resulting in a positive feedback. Once the thermal perturbation exceeds a critical (though as yet undefined) level, melting may decouple the ice from the bed, preventing further entrainment of till from thawed areas, and thus limiting the height and length of the drumlin.
影响因子：
4
作者：
Clark, Chris D.;Hughes, Anna L. C.;Ng, Felix S. L.
通讯作者：
Ng, Felix S. L.
影响因子：
3.4
作者：
Clark C
通讯作者：
Clark C
影响因子：
3.3
作者：
Chapwanya M
通讯作者：
Chapwanya M