DOI: 10.1016/j.quascirev.2014.07.022
Scopus记录号: 2-s2.0-84907334533
论文题名: Response of salt structures to ice-sheet loading: Implications for ice-marginal and subglacial processes
作者: Lang J. ; Hampel A. ; Brandes C. ; Winsemann J.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2014
卷: 101 起始页码: 217
结束页码: 233
语种: 英语
英文关键词: Central European Basin System
; Finite-element modelling
; Ice-sheet loading
; Salt structures
Scopus关键词: Elasticity
; Elastoplasticity
; Erosion
; Finite element method
; Glaciers
; Unloading
; Elasticity
; Elastoplasticity
; Erosion
; Finite element method
; Geology
; Glaciers
; Sedimentary rocks
; Strain
; Unloading
; Central European Basin System
; Controlling factors
; Elasto-plastic rheologies
; Erosion and deposition
; Finite element modelling
; Loading and unloading
; Salt structures
; Subglacial process
; Ice sheet
; Ice
; Ice
; displacement
; finite element method
; glacioisostasy
; ice margin
; ice sheet
; simulation
; subglacial environment
; subsidence
; deformation mechanism
; diapir
; geometry
; glacial environment
; moraine
; numerical model
; Pleistocene
; rheology
; salt dome
; salt tectonics
; spatial distribution
; structural response
; Germanic Basin
; Central Europe
英文摘要: During the past decades the effect of glacioisostatic adjustment has received much attention. However, the response of salt structures to ice-sheet loading and unloading is poorly understood. Our study aims to test conceptual models of the interaction between ice-sheet loading and salt structures by finite-element modelling. The results are discussed with regard to their implications for ice-marginal and subglacial processes. Our models consist of 2D plane-strain cross-sections, which represent simplified geological cross-sections from the Central European Basin System. The model layers represent (i) sedimentary rocks of elastoplastic rheology, (ii) a viscoelastic diapir and layer of salt and (iii) an elastoplastic basement. On top of the model, a temporarily variable pressure simulates the advance and retreat of an ice sheet. The durations of the individual loading phases were defined to resemble the durations of the Pleistocene ice advances in northern central Europe. The geometry and rheology of the model layers and the magnitude, spatial distribution and timing of ice-sheet loading were systematically varied to detect the controlling factors. All simulations indicate that salt structures respond to ice-sheet loading. An ice advance towards the diapir causes salt flow from the source layer below the ice sheet towards the diapir, resulting in an uplift of up to+4m. The diapir continues to rise as long as the load is applied to the source layer but not to the crest of the diapir. When the diapir is transgressed by the ice sheet the diapir is pushed down (up to-36m) as long as load is applied to the crest of the diapir. During and after ice unloading large parts of the displacement are compensated by a reversal of the salt flow. Plastic deformation of the overburden is restricted to the area immediately above the salt diapir. The displacements after unloading range between-3.1 and+2.7m. Larger displacements are observed in models with deep-rooted diapirs, thicker ice sheets, longer duration of the loading phase, thicker salt source layers and lower viscosity of the salt. The rise or fall of diapirs triggered or amplified by ice-sheet loading are likely to affect glacigenic deformation, erosion and deposition above the diapir and within the rim synclines. Ice-load induced uplift in front of an ice sheet will provide favourable conditions for the formation of push moraines, for example by creating a topographic obstacle and inclining potential detachments. Subglacial subsidence of salt structures will enhance erosion by providing a preferential drainage pathway and fracturing of the overburden of the salt structure and thereby contribute to the incision of tunnel valleys. However, the resulting displacements are probably too low to have a marked effect on the advance or retreat pattern of the ice sheets. © 2014 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60173
Appears in Collections: 过去全球变化的重建
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作者单位: Institut für Geologie, Leibniz Universität Hannover, Callinstraße 30, 30167 Hannover, Germany
Recommended Citation:
Lang J.,Hampel A.,Brandes C.,et al. Response of salt structures to ice-sheet loading: Implications for ice-marginal and subglacial processes[J]. Quaternary Science Reviews,2014-01-01,101