Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, Antarctica
Global Navigation Satellite System (GNSS) observations and ground-based timelapse photography obtained over the record-high 2019/2020 melt season are combined to characterise the flexure and fracture behaviour of a previously formed doline on George VI Ice Shelf, Antarctica. The GNSS timeseries show...
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Cambridge University Press
2024-01-01
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| Series: | Journal of Glaciology |
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| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143024000315/type/journal_article |
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| author | Alison F. Banwell Ian C. Willis Laura A. Stevens Rebecca L. Dell Douglas R. MacAyeal |
| author_facet | Alison F. Banwell Ian C. Willis Laura A. Stevens Rebecca L. Dell Douglas R. MacAyeal |
| author_sort | Alison F. Banwell |
| collection | DOAJ |
| description | Global Navigation Satellite System (GNSS) observations and ground-based timelapse photography obtained over the record-high 2019/2020 melt season are combined to characterise the flexure and fracture behaviour of a previously formed doline on George VI Ice Shelf, Antarctica. The GNSS timeseries shows a downward vertical displacement of the doline centre with respect to the doline rim of ~60 cm in response to loading from a central meltwater lake. The GNSS data also show a tens-of-days episode of rapid-onset, exponentially decaying horizontal displacement, where the horizontal distance between the doline rim and its centre increases by ~70 cm. We interpret this event as the initiation and/or widening of a fracture, aided by stress perturbations associated with meltwater loading in the doline basin. Viscous flexure modelling indicates that the meltwater loading generates tensile surface stresses exceeding 75 kPa. This, together with our timelapse photos of circular fractures around the doline, suggests the first such documentation of meltwater-loading-induced ‘ring fracture’ formation on an ice shelf, equivalent to the fracture type proposed as part of the chain-reaction lake drainage process involved in the 2002 breakup of the Larsen B Ice Shelf. |
| format | Article |
| id | doaj-art-ef590535795e49c49b108cbb50ec2e67 |
| institution | Kabale University |
| issn | 0022-1430 1727-5652 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj-art-ef590535795e49c49b108cbb50ec2e672025-01-16T21:51:29ZengCambridge University PressJournal of Glaciology0022-14301727-56522024-01-017010.1017/jog.2024.31Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, AntarcticaAlison F. Banwell0https://orcid.org/0000-0001-9545-829XIan C. Willis1https://orcid.org/0000-0002-0750-7088Laura A. Stevens2https://orcid.org/0000-0003-0480-8018Rebecca L. Dell3https://orcid.org/0000-0001-6617-3906Douglas R. MacAyeal4https://orcid.org/0000-0003-0647-6176Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, USAScott Polar Research Institute, University of Cambridge, Cambridge, UKDepartment of Earth Sciences, University of Oxford, Oxford, UKScott Polar Research Institute, University of Cambridge, Cambridge, UKDepartment of Geophysical Sciences, University of Chicago, Chicago, USAGlobal Navigation Satellite System (GNSS) observations and ground-based timelapse photography obtained over the record-high 2019/2020 melt season are combined to characterise the flexure and fracture behaviour of a previously formed doline on George VI Ice Shelf, Antarctica. The GNSS timeseries shows a downward vertical displacement of the doline centre with respect to the doline rim of ~60 cm in response to loading from a central meltwater lake. The GNSS data also show a tens-of-days episode of rapid-onset, exponentially decaying horizontal displacement, where the horizontal distance between the doline rim and its centre increases by ~70 cm. We interpret this event as the initiation and/or widening of a fracture, aided by stress perturbations associated with meltwater loading in the doline basin. Viscous flexure modelling indicates that the meltwater loading generates tensile surface stresses exceeding 75 kPa. This, together with our timelapse photos of circular fractures around the doline, suggests the first such documentation of meltwater-loading-induced ‘ring fracture’ formation on an ice shelf, equivalent to the fracture type proposed as part of the chain-reaction lake drainage process involved in the 2002 breakup of the Larsen B Ice Shelf.https://www.cambridge.org/core/product/identifier/S0022143024000315/type/journal_articlecrevassesglacier hydrologyice shelvesice dynamicsmelt – surface |
| spellingShingle | Alison F. Banwell Ian C. Willis Laura A. Stevens Rebecca L. Dell Douglas R. MacAyeal Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, Antarctica Journal of Glaciology crevasses glacier hydrology ice shelves ice dynamics melt – surface |
| title | Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, Antarctica |
| title_full | Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, Antarctica |
| title_fullStr | Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, Antarctica |
| title_full_unstemmed | Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, Antarctica |
| title_short | Observed meltwater-induced flexure and fracture at a doline on George VI Ice Shelf, Antarctica |
| title_sort | observed meltwater induced flexure and fracture at a doline on george vi ice shelf antarctica |
| topic | crevasses glacier hydrology ice shelves ice dynamics melt – surface |
| url | https://www.cambridge.org/core/product/identifier/S0022143024000315/type/journal_article |
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