Geomorphological criteria for identifying Pleistocene ice streams

Abstract Ice streams are critical regulatory mechanisms in contemporary ice sheets. It has been inferred that they also had a significant effect on the dynamics of former ice sheets. Subsequently, many people have invoked their widespread occurrence from a variety of formerly glaciated areas. Hypothesised locations, however, have often outweighed meaningful evidence. This paper addresses the problem, using the characteristics of contemporary ice streams as a basis for their identification from former ice-sheet beds. A convergence of knowledge gained from contemporary ice-stream research, coupled with theories of glacial geomorphology, allows several geomorphological criteria to be identified as suggestive signatures of ice-stream activity. It is envisaged that the geomorphological criteria developed here will introduce a more objective approach to the study of former ice streams. The criteria are used to construct conceptual land-system models of the beds of former ice streams, and it is hoped such models can provide an observational template upon which hypotheses of former ice streams can be better based.

[1]  R. Alley,et al.  Deformation of till beneath ice stream B, West Antarctica , 1986, Nature.

[2]  C. Laymon.  Glacial geology of western Hudson Strait, Canada, with reference to Laurentide Ice Sheet dynamics , 1992 .

[3]  S. Marshall,et al.  Geologic and topographic controls on fast flow in the Laurentide and Cordilleran Ice Sheets , 1996 .

[4]  John B. Anderson,et al.  What is happening to the west antarctic ice sheet , 1998 .

[5]  T. H. Jacka,et al.  Outlet Glacier and Mass-Budget Studies in Enderby, Kemp, and Mac. Robertson Lands, Antarctica , 1982, Annals of Glaciology.

[6]  A. J. Payne,et al.  Thermomechanical modelling of the Scandinavian ice sheet: implications for ice-stream formation , 1999, Annals of Glaciology.

[7]  C. Auton,et al.  Ice-proximal glaciomarine sedimentation and sea-level change in the inverness area, Scotland: A review of the deglaciation of a major ice stream of the British Late Devensian ice sheet , 1995 .

[8]  I. Evans.  Abraded rock landforms (whalebacks) developed under ice streams in mountain areas , 1996 .

[9]  S. Hodge,et al.  Satellite imagery of the onset of streaming flow of ice streams , 1996 .

[10]  T. F. Morris,et al.  DRUMLIN FIELDS, DISPERSAL TRAINS, and ICE STREAMS IN ARCTIC CANADA , 1988 .

[11]  C. Larsen,et al.  The role of the margins in the dynamics of an active ice stream , 1994 .

[12]  M. Punkari.  Function of the ice streams in the Scandinavian ice sheet: analyses of glacial geological data from southwestern Finland , 1994, Transactions of the Royal Society of Edinburgh: Earth Sciences.

[13]  R. Alley,et al.  Influence of subglacial geology on the position of a West Antarctic ice stream from seismic observations , 1998, Nature.

[14]  A. Mccabe,et al.  Identification and significance of ice-flow-transverse subglacial ridges (Rogen moraines) in northern central Ireland , 1997 .

[15]  T. F. Morris,et al.  Quaternary geology of Prince of Wales Island, Arctic Canada , 1992 .

[16]  R. Kwok,et al.  Greenland Ice Sheet Surface Properties and Ice Dynamics from ERS-1 SAR Imagery , 1993, Science.

[17]  Chris D. Clark,et al.  Large-scale ice-moulding: a discussion of genesis and glaciological significance , 1994 .

[18]  R. Alley,et al.  Sedimentation beneath ice shelves — the view from ice stream B , 1989 .

[19]  J. Laberg,et al.  Trough mouth fans — palaeoclimate and ice-sheet monitors , 1997 .

[20]  David J. A. Evans,et al.  Glaciers and Glaciation , 1997 .

[21]  C. Clark,et al.  A highly mobile Laurentide ice sheet revealed by satellite images of glacial lineations , 1990, Nature.

[22]  C. Bentley.  Antarctic ice streams: a review , 1987 .

[23]  T. Scambos,et al.  Influence of subglacial geology on the onset of a West Antarctic ice stream from aerogeophysical observations , 1998, Nature.

[24]  M. Funk,et al.  Mechanisms of fast flow in Jakobshavns Isbræ, West Greenland: Part I. Measurements of temperature and water level in deep boreholes , 1993, Journal of Glaciology.

[25]  S. R. Hicock,et al.  Lobal interactions, rheologic superposition, and implications for a Pleistocene ice stream on the continental shelf of British Columbia , 1995 .

[26]  C. J. Patterson.  Southern Laurentide ice lobes were created by ice streams: Des Moines Lobe in Minnesota, USA , 1997 .

[27]  Chris D. Clark,et al.  Mega‐scale glacial lineations and cross‐cutting ice‐flow landforms , 1993 .

[28]  P. Dongelmans.  Glacial dynamics of the Fennoscandian ice sheet : a remote-sensing study , 1996 .

[29]  C. J. Patterson.  Laurentide glacial landscapes: The role of ice streams , 1998 .

[30]  H Engelhardt,et al.  Physical Conditions at the Base of a Fast Moving Antarctic Ice Stream , 1990, Science.

[31]  Chris D. Clark,et al.  Glaciodynamic context of subglacial bedform generation and preservation , 1999, Annals of Glaciology.