On the rheology of till
On the rheology of till
复制标题
关于锄的流变学
作者：
A. Fowler
摘要：在最后一个冰河时代，冰下碛物的变形有助于引起某些冰川涌动、冰盖中冰流的快速运动以及与海因里希事件相关的冰盖涌动，以及随之而来的快速气候变化。它也可能是形成鼓膜的方式，而这些鼓膜反过来又可以充当大规模冰流的制动器。因此，在构建模型时了解冰块变形的速率以及它如何控制基础冰速度非常重要。近年来，出现了两种范式。一方面，理论家倾向于使用粘性流变学，尽管这缺乏定量支持。另一方面，现场和实验室研究表明，蒂尔具有可塑性。在本文中，我将研究后一种假设的一些动态后果，并展示粘性和塑性之间的二分法可能不像以前想象的那样明确。
Abstract The deformation of subglacial till is instrumental in causing certain glacier surges, the motion of rapid ice streams in ice sheets, and ice-sheet surges which are associated with Heinrich events, and consequent rapid climatic shifts, during the last ice age. It may also be the means whereby drumlins are formed, and these in turn may act as a brake on large-scale ice flow. It is therefore important in building models to understand the rate at which till deforms, and how this controls the basal ice velocity. In recent years, two paradigms have emerged. On the one hand, theoreticians have tended to use a viscous rheology, though this lacks quantitative support. On the other hand, field and laboratory studies suggest that till behaves plastically. In this paper I will examine some of the dynamic consequences of this latter assumption, and show how the dichotomy between viscous and plastic may be less clear-cut than previously thought.