DOI: 10.5194/tc-15-677-2021
论文题名: Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps
作者: Hellmann S. ; Kerch J. ; Weikusat I. ; Bauder A. ; Grab M. ; Jouvet G. ; Schwikowski M. ; Maurer H.
刊名: Cryosphere
ISSN: 19940416
出版年: 2021
卷: 15, 期: 2 起始页码: 677
结束页码: 694
语种: 英语
英文关键词: alpine environment
; crystallography
; glacier flow
; GNSS
; ice core
; microstructure
; polar region
; Rhone Glacier [Valais]
; Switzerland
; Switzerland
; Valais
英文摘要: Crystal orientation fabric (COF) analysis provides information about the c-axis orientation of ice grains and the associated anisotropy and microstructural information about deformation and recrystallisation processes within the glacier. This information can be used to introduce modules that fully describe the microstructural anisotropy or at least direction-dependent enhancement factors for glacier modelling. The COF was studied at an ice core that was obtained from the temperate Rhonegletscher, located in the central Swiss Alps. Seven samples, extracted at depths between 2 and 79 m, were analysed with an automatic fabric analyser. The COF analysis revealed conspicuous four-maxima patterns of the c-axis orientations at all depths. Additional data, such as microstructural images, produced during the ice sample preparation process, were considered to interpret these patterns. Furthermore, repeated high-precision global navigation satellite system (GNSS) surveying allowed the local glacier flow direction to be determined. The relative movements of the individual surveying points indicated longitudinal compressive stresses parallel to the glacier flow. Finally, numerical modelling of the ice flow permitted estimation of the local stress distribution. An integrated analysis of all the data sets provided indications and suggestions for the development of the four-maxima patterns. The centroid of the four-maxima patterns of the individual core samples and the coinciding maximum eigenvector approximately align with the compressive stress directions obtained from numerical modelling with an exception for the deepest sample. The clustering of the c axes in four maxima surrounding the predominant compressive stress direction is most likely the result of a fast migration recrystallisation. This interpretation is supported by air bubble analysis of large-area scanning macroscope (LASM) images. Our results indicate that COF studies, which have so far predominantly been performed on cold ice samples from the polar regions, can also provide valuable insights into the stress and strain rate distribution within temperate glaciers. © 2021 Institute of Electrical and Electronics Engineers Inc.. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164706
Appears in Collections: 气候变化与战略
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作者单位: Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland; Institute of Geophysics, ETH Zurich, Zurich, Switzerland; Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany; Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany; Department of Geography, University of Zurich, Zurich, Switzerland; Autonomous Systems Laboratory, ETH Zurich, Zurich, Switzerland; Paul Scherrer Institute, Villingen, Switzerland; GZG Computational Geoscience, Georg August University of Göttingen, Göttingen, Germany
Recommended Citation:
Hellmann S.,Kerch J.,Weikusat I.,et al. Crystallographic analysis of temperate ice on Rhonegletscher, Swiss Alps[J]. Cryosphere,2021-01-01,15(2)