DOI: 10.1016/j.quascirev.2017.12.003
Scopus记录号: 2-s2.0-85038106286
论文题名: Microscale evidence of liquefaction and its potential triggers during soft-bed deformation within subglacial traction tills
作者: Phillips E.R. ; Evans D.J.A. ; van der Meer J.J.M. ; Lee J.R.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2018
卷: 181 起始页码: 123
结束页码: 143
语种: 英语
英文关键词: Glacier bed deformation
; Icequakes
; Pressurised meltwater
; Till liquefaction
Scopus关键词: Liquefaction
; Slip forming
; Stick-slip
; Traction control
; Bed deformation
; Brittle structures
; Deformation result
; Icequakes
; Pressurised meltwater
; Saturated sediments
; Seismic activity
; Subglacial deformations
; Sediments
; bedform
; brittle deformation
; deformation
; ductile deformation
; glacier
; liquefaction
; meltwater
; sedimentary sequence
; sedimentary structure
; shear
; soft soil
; subglacial deposit
; till
; trigger mechanism
英文摘要: Published conceptual models argue that much of the forward motion of modern and ancient glaciers is accommodated by deformation of soft-sediments within the underlying bed. At a microscale this deformation results in the development of a range of ductile and brittle structures in water-saturated sediments as they accommodate the stresses being applied by the overriding glacier. Detailed micromorphological studies of subglacial traction tills reveal that these polydeformed sediments may also contain evidence of having undergone repeated phases of liquefaction followed by solid-state shear deformation. This spatially and temporally restricted liquefaction of subglacial traction tills lowers the shear strength of the sediment and promotes the formation of “transient mobile zones” within the bed, which accommodate the shear imposed by the overriding ice. This process of soft-bed sliding, alternating with bed deformation, facilitates glacier movement by way of ‘stick-slip’ events. The various controls on the slip events have previously been identified as: (i) the introduction of pressurised meltwater into the bed, a process limited by the porosity and permeability of the till; and (ii) pressurisation of porewater as a result of subglacial deformation; to which we include (iii) episodic liquefaction of water-saturated subglacial traction tills in response to glacier seismic activity (icequakes), which are increasingly being recognized as significant processes in modern glaciers and ice sheets. As liquefaction operates only in materials already at very low values of effective stress, its process-form signatures are likely indicative of glacier sub-marginal tills. © 2017 Natural Environment Research Council (NERC) as represented by the British Geological Survey (BGS) Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/112313
Appears in Collections: 气候减缓与适应
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作者单位: British Geological Survey, The Lyell Centre, Research Avenue South, Edinburgh, EH14 4AP, United Kingdom; Department of Geography, University of Durham, South Road, Durham, DH1 3LE, United Kingdom; School of Geography, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom; British Geological Survey, Keyworth, Nottingham, NG12 5GG, United Kingdom
Recommended Citation:
Phillips E.R.,Evans D.J.A.,van der Meer J.J.M.,et al. Microscale evidence of liquefaction and its potential triggers during soft-bed deformation within subglacial traction tills[J]. Quaternary Science Reviews,2018-01-01,181