Till beneath ice stream B: 3. Till deformation: Evidence and implications

Most of the velocity of ice stream B near the Upstream B camp (UpB), West Antarctica, appears to arise from deformation of a seismically detected, subglacial till layer that averages 6 m thick. Available evidence indicates that the entire thickness of this till layer is deforming and is eroding subjacent bedrock into flutes parallel to ice flow and hundreds of meters across. The resulting till flux beneath UpB is equivalent to an average erosion rate of about 0.4 mm yr−1 in the catchment area and suggests that till deltas tens of kilometers long have been deposited at the grounding line during the Holocene. Such deltas should be characterized by partial ice-till decoupling across a water film and by a small ice-air surface slope; they may have been discovered by recent geophysical work.

[1]  Charles R. Bentley,et al.  The morphology of ice streams A, B, and C, west Antarctica, and their environs , 1987 .

[2]  R. Alley,et al.  Till beneath ice stream B: 2. Structure and continuity , 1987 .

[3]  R. Alley,et al.  Till beneath ice stream B: 1. Properties derived from seismic travel times , 1987 .

[4]  G. Clarke.  Subglacial till: A physical framework for its properties and processes , 1987 .

[5]  R. Alley,et al.  Till beneath ice stream B: 4. A coupled ice-till flow model , 1987 .

[6]  C. Bentley,et al.  West Antarctic ice streams draining into the Ross Ice Shelf: Configuration and mass balance , 1987 .

[7]  E. Reimnitz,et al.  Extent and Nature of Ross Sea Unconformity in the Western Ross Sea, Antarctica , 1987 .

[8]  I. Whillans.  Force Budget of Ice Sheets , 1987 .

[9]  C. Bentley,et al.  Microearthquakes under and alongside ice stream B, Antarctica, detected by a new passive seismic array , 1987 .

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

[11]  R. Alley,et al.  Seismic measurements reveal a saturated porous layer beneath an active Antarctic ice stream , 1986, Nature.

[12]  P. Vornberger,et al.  Surface Features of Ice Stream B, Marie Byrd Land, West Antarctica , 1986, Annals of Glaciology.

[13]  R. N. Oldale.  Upper Wisconsinan Submarine End Moraines off Cape Ann, Massachusetts , 1985, Quaternary Research.

[14]  I. Smith,et al.  On the surging potential of polar ice streams: Part 2, Ice streams and physical characteristics of the Ross Sea drainage basin, West Antarctica , 1985 .

[15]  M. G. Grosval'd.  Glaciation of the continental shelves (part I) , 1984 .

[16]  R. Powell.  Glacimarine processes and inductive lithofacies modelling of ice shelf and tidewater glacier sediments based on quaternary examples , 1984 .

[17]  N. C. Myers,et al.  Sedimentation on the Ross Sea continental shelf, Antarctica , 1984 .

[18]  K. Jezek.  A modified theory of bottom crevasses used as a means for measuring the buttressing effect of ice shelves on inland ice sheets , 1984 .

[19]  David E. Thompson,et al.  Flow, thermal structure, and subglacial conditions of a surge-type glacier , 1984 .

[20]  I. Smith,et al.  A Three-Dimensional Time-Dependent Model of the West Antarctic Ice Sheet , 1984, Annals of Glaciology.

[21]  J. Weertman,et al.  Subglacial Water flow Under Ice Streams and West Antarctic Ice-Sheet Stability , 1982, Annals of Glaciology.

[22]  R. Bindschadler.  The Importance of Pressurized Subglacial Water in Separation and Sliding at the Glacier Bed (Abstract only) , 1982, Annals of Glaciology.

[23]  D. Macayeal,et al.  Derived Characteristics of the Ross Ice Shelf, Antarctica (Abstract only) , 1982, Annals of Glaciology.

[24]  L. Greischar,et al.  Isostatic equilibrium grounding line between the West Antarctic inland ice sheet and the Ross Ice Shelf , 1980, Nature.

[25]  R. Thomas,et al.  West Antarctic Ice Sheet: Present-Day Thinning and Holocene Retreat of the Margins , 1979, Science.

[26]  G. Boulton,et al.  Processes of Glacier Erosion on Different Substrata , 1979, Journal of Glaciology.

[27]  G. Boulton,et al.  Stability of Temperate Ice Caps and Ice Sheets Resting on Beds of Deformable Sediment , 1979, Journal of Glaciology.

[28]  A. Gow,et al.  On the Origin of Stratified Debris in Ice Cores from the Bottom of the Antarctic Ice Sheet , 1979, Journal of Glaciology.

[29]  R. Goldthwait.  Giant Grooves Made by Concentrated Basal Ice Streams , 1979, Journal of Glaciology.

[30]  B. Hallet.  Subglacial Regelation Water Film , 1979, Journal of Glaciology.

[31]  K. E. Rose,et al.  Characteristics of Ice Flow in Marie Byrd Land, Antarctica , 1979, Journal of Glaciology.

[32]  C. Bentley,et al.  A Model for Holocene Retreat of the West Antarctic Ice Sheet , 1978, Quaternary Research.

[33]  H. Engelhardt,et al.  Basal Sliding and Conditions at the Glacier Bed as Revealed by Bore-hole Photography , 1978, Journal of Glaciology.

[34]  T. Hughes.  West Antarctic Ice Streams , 1977 .

[35]  J. Weertman.  Penetration Depth of Closely Spaced Water-free Crevasses , 1977, Journal of Glaciology.

[36]  D. Sugden,et al.  GLACIERS AND LANDSCAPE: A GEO-MORPHOLOGICAL APPROACH , 2022 .

[37]  G. Boulton,et al.  The influence of genetic processes on some geotechnical properties of glacial tills , 1976, Quarterly Journal of Engineering Geology.

[38]  D. Dent,et al.  The Nature and Rates of Post-Depositional Changes in Recently Deposited Till from South-East Iceland , 1974 .

[39]  D. Dent,et al.  Subglacial Shearing and Crushing, and the Role of Water Pressures in Tills from South-East Iceland , 1974 .

[40]  J. Weertman.  General theory of water flow at the base of a glacier or ice sheet , 1972 .

[41]  M. R. Stauffer,et al.  Striations, giant grooves, and superposed drag folds, Interlake area, Manitoba , 1969 .

[42]  J. Weertman.  Water lubrication mechanism of glacier surges , 1969 .

[43]  Donald E. Garfield,et al.  Antarctic Ice Sheet: Preliminary Results of First Core Hole to Bedrock , 1968, Science.

[44]  A. Dreimanis,et al.  Orientation of till fabric by overriding glacier in the Saint Lawrence Valley , 1964 .

[45]  Å. Sundborg.  The River Klarälven a Study of Fluvial Processes , 1956 .

[46]  Filip Hjulstrom,et al.  Transportation of Detritus by Moving Water , 1955 .

[47]  F. Hjulström.  Studies of the morphological activity of rivers as illustrated by the River Fyris , 1935 .