Structures and Deformation in Glaciers and Ice Sheets

IF 25.2 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS
Stephen J. A. Jennings, Michael J. Hambrey
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引用次数: 28

Abstract

The aims of this review are to: (a) describe and interpret structures in valley glaciers in relation to strain history; and (b) to explore how these structures inform our understanding of the kinematics of large ice masses, and a wide range of other aspects of glaciology. Structures in glaciers give insight as to how ice deforms at the macroscopic and larger scale. Structures also provide information concerning the deformation history of ice masses over centuries and millennia. From a geological perspective, glaciers can be considered to be models of rock deformation, but with rates of change that are measurable on a human time-scale. However, structural assemblages in glaciers are commonly complex, and unraveling them to determine the deformation history is challenging; it thus requires the approach of the structural geologist. A wide range of structures are present in valley glaciers: (a) primary structures include sedimentary stratification and various veins; (b) secondary structures that are the result of brittle and ductile deformation include crevasses, faults, crevasse traces, foliation, folds, and boudinage structures. Some of these structures, notably crevasses, relate well to measured strain-rates, but to explain ductile structures analysis of cumulative strain is required. Some structures occur in all glaciers irrespective of size, and they are therefore recognizable in ice streams and ice shelves. Structural approaches have wide (but as yet under-developed potential) application to other sub-disciplines of glaciology, notably glacier hydrology, debris entrainment and transfer, landform development, microbiological investigations, and in the interpretation of glacier-like features on Mars.

冰川和冰原的结构和变形
本综述的目的是:(a)描述和解释与应变历史有关的山谷冰川结构;(b)探索这些结构如何告知我们对大冰块运动学的理解,以及冰川学的其他广泛方面。冰川的结构提供了关于冰如何在宏观和更大尺度上变形的见解。这些结构也提供了关于几个世纪和几千年来冰块变形历史的信息。从地质学的角度来看,冰川可以被认为是岩石变形的模型,但其变化率在人类的时间尺度上是可以测量的。然而,冰川中的结构组合通常是复杂的,解开它们以确定变形历史是具有挑战性的;因此,它需要构造地质学家的方法。峡谷冰川的构造种类繁多:(A)原生构造包括沉积分层和各种脉体;(b)次生构造是脆性和韧性变形的结果,包括裂缝、断层、裂缝痕迹、片理、褶皱和边界构造。其中一些结构,特别是裂缝,与测量的应变率有很好的关系,但为了解释延性结构,需要对累积应变进行分析。有些结构不论大小大小,都存在于所有冰川中,因此在冰流和冰架中都能辨认出来。结构方法在冰川学的其他分支学科中有广泛的应用(但潜力尚未开发),特别是冰川水文学、碎片夹带和转移、地貌发育、微生物研究以及对火星冰川样特征的解释。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Reviews of Geophysics
Reviews of Geophysics 地学-地球化学与地球物理
CiteScore
50.30
自引率
0.80%
发文量
28
审稿时长
12 months
期刊介绍: Geophysics Reviews (ROG) offers comprehensive overviews and syntheses of current research across various domains of the Earth and space sciences. Our goal is to present accessible and engaging reviews that cater to the diverse AGU community. While authorship is typically by invitation, we warmly encourage readers and potential authors to share their suggestions with our editors.
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