scholarly journals Melting–Refreezing at the Glacier Sole and the Isotopic Composition of the Ice

1982 ◽  
Vol 28 (98) ◽  
pp. 35-42 ◽  
Author(s):  
J. Jouzel ◽  
R. A. Souchez
Keyword(s):  
Isotopic Composition ◽  
Water System ◽  
Alpine Glacier ◽  
Basal Ice ◽  
Distribution Of Points ◽  
Rock Interface ◽  
Ice Water

AbstractA model for the isotopic composition in δD and δ18O of ice formed by refreezing at the glacier sole is developed. This model predicts relatively well the distribution of points representing samples from basal layers of an Arctic and an Alpine glacier on a δD–δ18O diagram. The frozen fraction which is the part of the liquid that refreezes can be determined for each basal ice layer. This may have implications on the study of the ice–water system at the ice–rock interface.

scholarly journals Melting–Refreezing at the Glacier Sole and the Isotopic Composition of the Ice

1982 ◽  
Vol 28 (98) ◽  
pp. 35-42 ◽  
Author(s):  
J. Jouzel ◽  
R. A. Souchez
Keyword(s):  
Isotopic Composition ◽  
Water System ◽  
Alpine Glacier ◽  
Basal Ice ◽  
Distribution Of Points ◽  
Rock Interface ◽  
Ice Water

AbstractA model for the isotopic composition inδD andδ18O of ice formed by refreezing at the glacier sole is developed. This model predicts relatively well the distribution of points representing samples from basal layers of an Arctic and an Alpine glacier on aδD–δ18O diagram. The frozen fraction which is the part of the liquid that refreezes can be determined for each basal ice layer. This may have implications on the study of the ice–water system at the ice–rock interface.

scholarly journals Subglacial hydrology and the formation of ice streams

2014 ◽  
Vol 470 (2161) ◽  
pp. 20130494 ◽  
Author(s):  
T. M Kyrke-Smith ◽  
R. F Katz ◽  
A. C Fowler
Keyword(s):  
Ice Sheet ◽  
Water System ◽  
Coupled Model ◽  
Water Film ◽  
Mass Conservation ◽  
Ice Streams ◽  
Base Level ◽  
Ice Sheet Dynamics ◽  
Ice Water ◽  
Subglacial Meltwater

Antarctic ice streams are associated with pressurized subglacial meltwater but the role this water plays in the dynamics of the streams is not known. To address this, we present a model of subglacial water flow below ice sheets, and particularly below ice streams. The base-level flow is fed by subglacial melting and is presumed to take the form of a rough-bedded film, in which the ice is supported by larger clasts, but there is a millimetric water film which submerges the smaller particles. A model for the film is given by two coupled partial differential equations, representing mass conservation of water and ice closure. We assume that there is no sediment transport and solve for water film depth and effective pressure. This is coupled to a vertically integrated, higher order model for ice-sheet dynamics. If there is a sufficiently small amount of meltwater produced (e.g. if ice flux is low), the distributed film and ice sheet are stable, whereas for larger amounts of melt the ice–water system can become unstable, and ice streams form spontaneously as a consequence. We show that this can be explained in terms of a multi-valued sliding law, which arises from a simplified, one-dimensional analysis of the coupled model.

scholarly journals Ice Fabrics and Petrography, Meserve Glacier, Antarctica

1974 ◽  
Vol 13 (68) ◽  
pp. 285-306 ◽  
Author(s):  
P.W. Anderton
Keyword(s):  
Steady State ◽  
Stress Level ◽  
Optic Axis ◽  
Near Surface ◽  
Fine Grained ◽  
Basal Ice ◽  
Single Maximum ◽  
Fabric Analysis ◽  
Rock Interface ◽  
Ice Fabrics

Results of petrographic and fabric analysis of fine-grained cold ice from the tongue of Meserve Glacier, Antarctica, are described. Most of the basal ice is remarkably uniform in texture and shows an optic-axis fabric with a single strong maximum, which is consistent with the steady-state conditions of flow. Within 0.5 m of the ice–rock interface, irregularities in the bed cause flow perturbations which are correlated with recrystallization and changes in fabric of the ice. Optic-axis fabrics in the basal ice show close symmetry relationships with dimensional fabric and deformation symmetry. Grain-size of the ice increases towards the surface of the glacier and the single maximum of the optic-axis fabric undergoes a rotation about the flow vector. In the near surface, where strain-rates are relatively much lower, the optic-axis fabric symmetry is not closely related to either deformation symmetry or the dimensional fabric. Syntectonic recrystallization of ice throughout the glacier tongue characteristically produces a strong single-maximum fabric, the orientation of which in relation to the stress field is apparently determined by stress level. Under steady-state conditions of flow, the strength of the maximum also appears to be a function of stress level.

Isotopic composition of vent discharge from the Matanuska Glacier, Alaska: Implications for the origin of basal ice

1999 ◽  
Author(s):  
Daniel D. Titus ◽  
Grahame J. Larson ◽  
Jeffrey C. Strasser ◽  
Daniel E. Lawson ◽  
Edward B. Evenson ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Basal Ice ◽  
Matanuska Glacier

scholarly journals Optical Measurements of Water Lenses in Ice

1987 ◽  
Vol 33 (114) ◽  
pp. 159-161 ◽  
Author(s):  
M.E.R. Walford ◽  
D.W. Roberts ◽  
I. Hill
Keyword(s):  
Grain Boundary ◽  
Specific Surface ◽  
Dihedral Angle ◽  
Focal Length ◽  
Water System ◽  
Optical Measurements ◽  
Free Energies ◽  
Minor Revision ◽  
Experimental Values ◽  
Ice Water

AbstractThe dihedral angle of water at a grain boundary in ice is found, by measuring the optical focal length of lenticular water inclusions, to be 33.6 ± 0.7°. The new result leads to only minor revision of published experimental values of specific surface free energies in the ice–water system (Ketcham and Hobbs, 1969).

scholarly journals δD – δ18O Relationships in Ice Formed by Subglacial Freezing: Paleoclimatic Implications

1985 ◽  
Vol 31 (109) ◽  
pp. 229-232 ◽  
Author(s):  
R. A. Souchez ◽  
J. M. de Groote
Keyword(s):  
Computer Simulation ◽  
Isotopic Composition ◽  
Ice Sheets ◽  
Ice Cores ◽  
System Model ◽  
Polar Ice ◽  
Bottom Part ◽  
Basal Ice ◽  
Polar Ice Sheets ◽  
Glacier Ice

AbstractA freezing slope, distinct from that of precipitation, is displayed on a δD–δ18O diagram by basal ice in different circumstances. However, if the subglacial reservoir allowed to freeze is mixed in the course of time with an input having a lighter isotopic composition, basal ice cannot be distinguished from glacier ice in terms of slope. Such a situation is encountered at the base of Grubengletscher and is indicated by a computer simulation using the open-system model of Souchez and Jouzel (1984). Suggested implications for the paleoclimatic interpretation of deep ice cores recovered from the bottom part of polar ice sheets are given.

Approximate solution to the freezing of the ice-water system

1972 ◽  
Vol 8 (4) ◽  
pp. 1083-1086 ◽  
Author(s):  
Stephen D. Foss ◽  
Stephen S. T. Fan
Keyword(s):  
Approximate Solution ◽  
Water System ◽  
Ice Water

scholarly journals Estimation of Basal Heat Flux Over Ice-Covered Areas From Radio Echo-Sounding

1979 ◽  
Vol 23 (89) ◽  
pp. 405-406 ◽  
Author(s):  
David J. Drewry
Keyword(s):  
Heat Flux ◽  
Vertical Temperature Profile ◽  
Precise Calculation ◽  
Slow Fading ◽  
Basal Ice ◽  
Radio Echo Sounding ◽  
Limiting Condition ◽  
Ice Water ◽  
Fundamental Boundary ◽  
Echo Sounding

AbstractTwo fundamental boundary conditions for basal ice may be recognized by radio echo-sounding: ice–rock and ice–water interfaces. The latter is identified on the basis of horizontal echoes displaying slow fading, high persistent returned power, and with a reflection coefficient lying between –1 and –3 dB. Such water, located beneath an ice sheet, provides a known limiting condition to the vertical temperature profile and allows more precise calculation of the basal temperature gradient and estimation of the heat flux through the sole.

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