RATE CONTROLLING PROCESSES IN THE CREEP OF POLAR GLACIER ICE
Torsion tests have been carried out on artificial ice and on samples cut from an ice core obtained at South Pole Station. Results give a stress exponent smaller than 2 for stresses lower than 0.1 MPa. Analysis of the inclinometer survey of the Dye 3 borehole yields the same result. The deformation m...
| Main Authors: | , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
HAL CCSD
1987
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| Subjects: | |
| Online Access: | https://hal.science/jpa-00226280 https://hal.science/jpa-00226280/document https://hal.science/jpa-00226280/file/ajp-jphyscol198748C134.pdf https://doi.org/10.1051/jphyscol:1987134 |
| Summary: | Torsion tests have been carried out on artificial ice and on samples cut from an ice core obtained at South Pole Station. Results give a stress exponent smaller than 2 for stresses lower than 0.1 MPa. Analysis of the inclinometer survey of the Dye 3 borehole yields the same result. The deformation mechanisms of polar ice at low stresses are reviewed. A Newtonian viscosity may be expected with dislocation glide accommodated by grainboundary migration linked with graingrowth. However, rotation of crystals by dislocation glide and strain-induced boundary migration are complementary and efficient mechanisms to accommodate the incompatible plastic deformation between grains of different lattice orientation. These deformation mechanisms concern a great part of polar ice. |
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