Glacial Abrasion and Sliding: their Dependence on the Debris Concentration in Basal Ice
Glacial Abrasion and Sliding: their Dependence on the Debris Concentration in Basal Ice
复制标题
冰川磨损和滑动：它们对基底冰碎片浓度的依赖性
作者：
B. Hallet
建立了一个温带冰川侵蚀基岩的模型，该模型考虑了冰岩界面上分散的岩石碎块对冰川滑动的显著阻碍作用。碎石浓度增加到一个相对较低的值以上，可以通过减少岩石碎石的流量和将碎石压在床层上的有效力来降低磨损率。简单波状床层的磨耗在相对较低的磨屑浓度下最快，在此浓度以上，磨损量与磨屑含量成反比。对于任意几何形状但粗糙度较低的床层，预计也会出现类似的浓度依赖关系。滑动的冰川将倾向于磨损，直到基冰几乎停滞，在这一点上，各种大小的岩石开始堆积在海床上。
A model of bedrock abrasion by a temperate glacier is developed that takes into account the significant impeding effect of scattered rock fragments at the ice-rock interface on glacier sliding. An increase in the debris concentration above a relatively low value can reduce the abrasion rate by decreasing both the flux of rock fragments and the effective forces which press fragments against the bed. Abrasion of a simple wavy bed is shown to be most rapid for a relatively low debris concentration above which the abrasion varies inversely with the debris content. A similar concentration dependence of abrasion is expected for beds of arbitrary geometry but low roughness. Sliding glaciers will tend to abrade until the basal ice is nearly stagnant at which point rocks of all sizes start to lodge against the bed.