Deglacial land emergence and lateral upper-mantle heterogeneity in the Svalbard Archipelago--II. Extended results for high-resolution load models
In Paper I (Breuer & Wolf 1995), a preliminary interpretation of the postglacial land emergence observed at a restricted set of six locations in the Svalbard Archipelago was given. The study was based on a simple model of the Barents Sea ice sheet and suggested increases in lithosphere thickness...
| Published in: | Geophysical Journal International |
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| Main Authors: | , |
| Format: | Text |
| Language: | English |
| Published: |
Oxford University Press
1996
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| Subjects: | |
| Online Access: | http://gji.oxfordjournals.org/cgi/content/short/127/1/125 https://doi.org/10.1111/j.1365-246X.1996.tb01539.x |
| Summary: | In Paper I (Breuer & Wolf 1995), a preliminary interpretation of the postglacial land emergence observed at a restricted set of six locations in the Svalbard Archipelago was given. The study was based on a simple model of the Barents Sea ice sheet and suggested increases in lithosphere thickness and asthenosphere viscosity with increasing distance from the continental margin. In the present paper, the newly developed high-resolution load model. BARENTS-2, and land-uplift observations from an extended set of 25 locations are used to study further the possibility of resolving lateral heterogeneity in the upper mantle below the northern Barents Sea. A comparison of the calculated and observed uplift values shows that the lithosphere thickness is not well resolved by the observations, although values above 110 km are most common for this parameter. In contrast to this, there are indications of a lateral variation of asthenosphere viscosity. Whereas values in the range 1018−1020Pa s are inferred for locations close to the continental margin, 1020− 1021 Pa s are suggested further away from the margin. A study of the sensitivity of the values found for lithosphere thickness and asthenosphere viscosity to modifications of load model BARENTS-2 shows that such modifications can be largely accommodated by appropriate changes in lithosphere thickness, whereas the suggested lateral variation of asthenosphere viscosity is essentially unaffected. An estimate of the influence of the Fennoscandian ice sheet leads to the conclusion that its neglect results in an underestimation of the thickness of the Barents Sea ice sheet by about 10 per cent. |
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