CLIMATIC CONTROLS ON GLACIAL EROSION – INSIGHTS FROM NUMERICAL GLACIAL LANDSCAPE EVOLUTION MODELING

Abstract. Shear stress at the base of glaciers exerts a significant control on basal sliding and hence also glacial erosion in arctic and high-altitude areas. However, the inaccessible nature of glacial beds complicates empirical studies of basal shear stress, and little is therefore known of its spatial and temporal distribution. In this study we seek to improve our understanding of basal shear stress using a higher-order numerical ice model (iSOSIA). In order to test the validity of the higher-order model, we first compare the detailed distribution of basal shear stress in iSOSIA and in a three-dimensional full-Stokes model (Elmer/Ice). We find that iSOSIA and Elmer/Ice predict similar first-order stress and velocity patterns, and that differences are restricted to local variations at length scales of the order of the grid resolution. In addition, we find that subglacial shear stress is relatively uniform and insensitive to subtle changes in local topographic relief. Following the initial comparison studies, we use iSOSIA to investigate changes in basal shear stress as a result of landscape evolution by glacial erosion. The experiments with landscape evolution show that subglacial shear stress decreases as glacial erosion transforms preglacial V-shaped valleys into U-shaped troughs. These findings support the hypothesis that glacial erosion is most efficient in the early stages of glacial landscape development.

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The glacial geomorphology of the Antarctic ice sheet bed

Antarctic Science ◽

10.1017/s0954102014000212 ◽

2014 ◽

Vol 26 (6) ◽

pp. 724-741 ◽

Cited By ~ 25

Author(s):

Stewart S.R. Jamieson ◽

Chris R. Stokes ◽

Neil Ross ◽

David M. Rippin ◽

Robert G. Bingham ◽

...

Keyword(s):

Large Scale ◽

Landscape Evolution ◽

Ice Sheets ◽

Ice Sheet ◽

Glacial Erosion ◽

Antarctic Ice Sheet ◽

The Past ◽

Valley Network ◽

The Antarctic ◽

Antarctic Ice Sheets

AbstractIn 1976, David Sugden and Brian John developed a classification for Antarctic landscapes of glacial erosion based upon exposed and eroded coastal topography, providing insight into the past glacial dynamics of the Antarctic ice sheets. We extend this classification to cover the continental interior of Antarctica by analysing the hypsometry of the subglacial landscape using a recently released dataset of bed topography (BEDMAP2). We used the existing classification as a basis for first developing a low-resolution description of landscape evolution under the ice sheet before building a more detailed classification of patterns of glacial erosion. Our key finding is that a more widespread distribution of ancient, preserved alpine landscapes may survive beneath the Antarctic ice sheets than has been previously recognized. Furthermore, the findings suggest that landscapes of selective erosion exist further inland than might be expected, and may reflect the presence of thinner, less extensive ice in the past. Much of the selective nature of erosion may be controlled by pre-glacial topography, and especially by the large-scale tectonic structure and fluvial valley network. The hypotheses of landscape evolution presented here can be tested by future surveys of the Antarctic ice sheet bed.

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On the role of hydrologic processes in soil and landscape evolution modeling: concepts, complications and partial solutions

Earth-Science Reviews ◽

10.1016/j.earscirev.2018.09.001 ◽

2018 ◽

Vol 185 ◽

pp. 1088-1106 ◽

Cited By ~ 12

Author(s):

W.M. van der Meij ◽

A.J.A.M. Temme ◽

H.S. Lin ◽

H.H. Gerke ◽

M. Sommer

Keyword(s):

Landscape Evolution ◽

Hydrologic Processes ◽

Evolution Modeling

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The Role of Fluvial and Glacial Erosion in Landscape Evolution: The Ben Ohau Range, New Zealand

Earth Surface Processes and Landforms ◽

10.1002/(sici)1096-9837(199703)22:3<317::aid-esp760>3.0.co;2-i ◽

1997 ◽

Vol 22 (3) ◽

pp. 317-327 ◽

Cited By ~ 49

Author(s):

Martin Kirkbride ◽

David Matthews

Keyword(s):

New Zealand ◽

Landscape Evolution ◽

Glacial Erosion

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Early-Middle Pleistocene Beheading of the River Thames

Géographie physique et Quaternaire ◽

10.7202/033131ar ◽

2007 ◽

Vol 51 (3) ◽

pp. 327-336 ◽

Cited By ~ 7

Author(s):

Colin A. Whiteman ◽

James Rose

Keyword(s):

Climate Change ◽

Recent Work ◽

Landscape Evolution ◽

Middle Pleistocene ◽

Glacial Erosion ◽

Quaternary Period ◽

Quaternary Climate ◽

River Capture ◽

River Thames

ABSTRACT This paper marks the centenary of the first of three articles by W.M. Davis on the beheading of the Thames, beginning with a statement of his capture hypothesis in 1895 and concluding with attempts to explain anomalous misfit streams in 1899 and 1909. It discusses Davis's classic thesis of river capture by slow, long-term landscape evolution and his apparent reluctance to accept the fact of rapid Quaternary climate change. In contrast, recent work based on lithostratigraphy, biostratigraphy and morphostratigraphy emphasises the dynamism of the Quaternary Period and its influence on river capture. Possible mechanisms for the beheading of the Thames, tectonism, glacial erosion and conventional Davisian river capture, and the timing of the event, are discussed. In conclusion, the paper summarises known and unknown components of the problem of the beheading of the Thames, and discusses the extent of Davis's influence on later Thames studies.

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