DOI: 10.1016/j.quascirev.2017.06.021
Scopus记录号: 2-s2.0-85021265377
论文题名: Subglacial till formation: Microscale processes within the subglacial shear zone
作者: Hart J.K.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2017
卷: 170 起始页码: 26
结束页码: 44
语种: 英语
英文关键词: Geomorphology
; Glacial
; Glaciology
; Present
; Subglacial deformation
; Subglacial processes
; Thin section
; Till genesis
; Western Europe
Scopus关键词: Deformation
; Geomorphology
; Glacial geology
; Process monitoring
; Scanning electron microscopy
; Shear strain
; Structural geology
; Glacial
; Glaciology
; Present
; Subglacial deformations
; Subglacial process
; Thin section
; Till genesis
; Western Europe
; Lithology
英文摘要: This was a study of subglacial deformation till genesis from a modern temperate glacier, at Skálafellsjökull, Iceland. Detailed microscale properties of till samples (from Scanning Electron Microscope [SEM] and thin section analysis) were examined from a glacial site with in situ subglacial process monitoring and an exposed subglacial surface in the foreland. Two lithofacies were examined, a grey sandy till derived from the ash and basalt, and a silty reddish brown till derived from oxidized paleosols and/or tephra layers. These also represented a clay-content continuum from low (0.3%) to high (22.3%). The evolution from debris to subglacial till was investigated. This included a reduction in grain-size (21% for grey lithology, 13% reddish brown lithology), and reduction in rounding (RA) (32% for the grey lithology, 26% for the reddish brown lithology), and the quantification and analysis of the different grain erosion/comminution processes in the resultant till. It was shown that the microstructures within a till were dependent on shear strain and glaciological conditions (deformation history). The low clay content tills were dominated by linear structures (lineations and boudins, and anisotropic microfabric) whilst the higher clay content tills were dominated by rotational structures (turbates and plaster, and isotropic microfabric). These results are important in our understanding of the formation of both modern and Quaternary tills and informs our reconstruction of past glacial dynamics. © 2017 资助项目: The author would like to thank the Glacsweb Iceland 2008/2011 and 2012 teams for help with probe development and data collection
; and to Mark Dover in the Cartographic Unit for figure preparation. Thanks also go to Anders Damsgaard and two anonymous reviewers for very constructive reviews, which improved the quality of the manuscript. This research was funded by EPSRC (EP/C511050/1), Leverhulme (F/00 180/AK) and the National Geographic (GEFNE45-12) and the GPR and Leica 1200 GPS units were loaned from the NERC Geophysical Equipment Facility.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59145
Appears in Collections: 过去全球变化的重建
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作者单位: Geography and Environment, University of Southampton, United Kingdom
Recommended Citation:
Hart J.K.. Subglacial till formation: Microscale processes within the subglacial shear zone[J]. Quaternary Science Reviews,2017-01-01,170