Geomorphology under ice streams: Moving from form to process
Geomorphology under ice streams: Moving from form to process
复制标题
冰流下的地貌：从形式到过程
DOI：
10.1002/esp.4259
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发表时间：
2017
影响因子：
3.3
通讯作者：
Stokes C
中科院分区：
文献类型：
--
作者：
Stokes C
冰流是冰盖物质平衡的组成部分，直接影响海平面。它们的流动是由冰床界面上的过程控制的，这些过程创造了地形，而地形又通过它们对床面地形和基本剪切力的影响来调节冰流动力学。因此，冰流地貌对于理解和模拟冰流和冰盖动力学至关重要。本文从历史的角度回顾了我们对冰流地貌认识的发展，重点介绍了现代冰流和古冰流的研究已经在多大程度上结合起来，使我们从几乎完全无知的立场转向对冰流河床形态的详细了解。在20世纪70年代和80年代，我们的知识有限，主要是通过对南极洲现代冰川床的地球物理调查收集的。很少有古冰川被有把握地辨认出来。然而，在20世纪90年代，冰川地貌学家开始认识到它们独特的地貌，其中包括高度拉长的巨型冰川线条、冰流剪切边缘冰川和主要沉积中心的独特模式。然而，对遗迹特征的研究几乎不能说明这种地貌演变的时间尺度和冰川条件。21世纪初，通过继续努力以更高的分辨率仔细研究现代冰川床，这一问题开始得到解决，但我们目前对地形与过程的关系的理解仍然存在很大的不确定性，特别是关于沉积物侵蚀、输送和沉积的机制和时间尺度，以及这些如何导致冰下河床的生长和衰退。这是下一个关键挑战，需要冰川学、冰川地貌学、沉积学和数值模拟之间更密切的合作，以及更复杂的方法来量化和分析来自活动冰流下的地貌数据的预期增长。©2017作者。地球表面过程和地貌由John Wiley&Sons Ltd.出版。
Ice streams are integral components of an ice sheet's mass balance and directly impact on sea level. Their flow is governed by processes at the ice‐bed interface which create landforms that, in turn, modulate ice stream dynamics through their influence on bed topography and basal shear stresses. Thus, ice stream geomorphology is critical to understanding and modelling ice streams and ice sheet dynamics. This paper reviews developments in our understanding of ice stream geomorphology from a historical perspective, with a focus on the extent to which studies of modern and palaeo‐ice streams have converged to take us from a position of near‐complete ignorance to a detailed understanding of their bed morphology. During the 1970s and 1980s, our knowledge was limited and largely gleaned from geophysical investigations of modern ice stream beds in Antarctica. Very few palaeo‐ice streams had been identified with any confidence. During the 1990s, however, glacial geomorphologists began to recognise their distinctive geomorphology, which included distinct patterns of highly elongated mega‐scale glacial lineations, ice stream shear margin moraines, and major sedimentary depocentres. However, studying relict features could say little about the time‐scales over which this geomorphology evolved and under what glaciological conditions. This began to be addressed in the early 2000s, through continued efforts to scrutinise modern ice stream beds at higher resolution, but our current understanding of how landforms relate to processes remains subject to large uncertainties, particularly in relation to the mechanisms and time‐scales of sediment erosion, transport and deposition, and how these lead to the growth and decay of subglacial bedforms. This represents the next key challenge and will require even closer cooperation between glaciology, glacial geomorphology, sedimentology, and numerical modelling, together with more sophisticated methods to quantify and analyse the anticipated growth of geomorphological data from beneath active ice streams. © 2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.
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