Relative sea‐level history and isostatic rebound in Newfoundland, Canada
The island of Newfoundland, Canada, is situated close to the former margins of the Laurentide ice sheet. The post‐glacial sea‐level history is complex, dominated by the effects of an ice‐marginal crustal forebulge produced by isostatic deformation of the lithosphere. Marine fossils found above prese...
| Published in: | Boreas |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
1994
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| Online Access: | http://dx.doi.org/10.1111/j.1502-3885.1994.tb00944.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.1994.tb00944.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.1994.tb00944.x |
| Summary: | The island of Newfoundland, Canada, is situated close to the former margins of the Laurentide ice sheet. The post‐glacial sea‐level history is complex, dominated by the effects of an ice‐marginal crustal forebulge produced by isostatic deformation of the lithosphere. Marine fossils found above present sea‐level can be 14 C dated, and examination of the temporal and geographical distribution of these 14 C dates in combination with geomorphological indicators of past sea‐levels indicates regional trends of relative sea‐level change. For most of the island (apart from the Northern Peninsula) no samples have been recovered that date younger than 8000 BP. suggesting that sea‐level lay below the present one in these areas for the last 8000 years. The same areas commonly show geomorphological evidence for stands of sea‐level both above and below present sea‐level. This evidence is interpreted as showing that over most of Newfoundland, following deglaciation, sea‐level fell to below present levels, and subsequently rose to the modern level. Exceptions to this pattern are the north of the Northern Peninsula, which shows a history of continuous emergence, or a more complex pattern of sea‐levels falling below present, subsequently rising above present, and currently falling; and the northeast Avalon Peninsula, which may have had sea‐levels below present throughout post glacial times. This pattern of relative sea‐level change is interpreted as being mostly due to isostatic recovery, with the main factor being northerly migration of the forebulge. Mapping the time at which sea‐level fell below the present level allows estimation of the rate of northerly migration and collapse of the forebulge at between 4.5 and 11 km/100 years; this is considerably faster than previous estimates. |
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