DOI: 10.1016/j.quascirev.2016.07.012
论文题名: Distribution and characteristics of overdeepenings beneath the Greenland and Antarctic ice sheets: Implications for overdeepening origin and evolution
作者: Patton H. ; Swift D.A. ; Clark C.D. ; Livingstone S.J. ; Cook S.J.
刊名: Quaternary Science Reviews
出版年: 2016
卷: 148 起始页码: 128
结束页码: 145
语种: 英语
英文关键词: Geomorphology
; Glacial erosion
; Ice sheet
; Landscape evolution
; Overdeepening
Scopus关键词: Erosion
; Feedback
; Geographic information systems
; Geomorphology
; Glacial geology
; Glaciers
; Hydrology
; Ice control
; Sediment transport
; Antarctic ice sheets
; Formation and evolutions
; Glacial erosion
; Ice sheet
; Landscape evolutions
; Overdeepening
; Quantitative empirical studies
; Subglacial hydrology
; Ice
; continental shelf
; flow stability
; glacier dynamics
; ice flow
; ice sheet
; incised valley
; quality control
; quantitative analysis
; sediment transport
; sedimentation
; trough
; Antarctic Ice Sheet
; Antarctica
; Arctic
; Greenland
; Greenland Ice Sheet
; Siple Coast
; West Antarctica
英文摘要: Glacier bed overdeepenings are ubiquitous in glacier systems and likely exert significant influence on ice dynamics, subglacial hydrology, and ice stability. Understanding of overdeepening formation and evolution has been hampered by an absence of quantitative empirical studies of their distribution and morphology, with process insights having been drawn largely from theoretical or numerical studies. To address this shortcoming, we first map the distribution of potential overdeepenings beneath the Antarctic and Greenland ice sheets using a GIS-based algorithm that identifies closed-contours in the bed topography and then describe and analyse the characteristics and metrics of a subset of overdeepenings that pass further quality control criteria. Overdeepenings are found to be widespread, but are particularly associated with areas of topographically laterally constrained ice flow, notably near the ice sheet margins where outlet systems follow deeply incised troughs. Overdeepenings also occur in regions of topographically unconstrained ice flow (for example, beneath the Siple Coast ice streams and on the Greenland continental shelf). Metrics indicate that overdeepening growth is generally allometric and that topographic confinement of ice flow in general enhances overdeepening depth. However, overdeepening depth is skewed towards shallow values – typically 200–300 m – indicating that the rate of deepening slows with overdeepening age. This is reflected in a decline in adverse slope steepness with increasing overdeepening planform size. Finally, overdeepening long-profiles are found to support headward quarrying as the primary factor in overdeepening development. These observations support proposed negative feedbacks related to hydrology and sediment transport that stabilise overdeepening growth through sedimentation on the adverse slope but permit continued overdeepening planform enlargement by processes of headward erosion. © 2016 资助项目: Swift, D.A.
; Department of Geography, University of Sheffield, Winter Street, United Kingdom
; 电子邮件: d.a.swift@sheffield.ac.uk
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59489
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Geography, University of Sheffield, Winter Street, Sheffield, United Kingdom; CAGE—Centre for Arctic Gas Hydrate Environment and Climate, Department of Geology, UiT The Arctic University of Norway, Tromsø, Norway; School of Science and the Environment, Manchester Metropolitan University, Chester Street, Manchester, United Kingdom
Recommended Citation:
Patton H.,Swift D.A.,Clark C.D.,et al. Distribution and characteristics of overdeepenings beneath the Greenland and Antarctic ice sheets: Implications for overdeepening origin and evolution[J]. Quaternary Science Reviews,2016-01-01,148