Rates of Holocene chemical weathering, `Little Ice Age' glacial erosion and implications for Schmidt-hammer dating at a glacier—foreland boundary, Fåbergstølsbreen, southern Norway
Average rates of Holocene chemical weathering and `Little Ice Age' glacial erosion of bedrock are estimated across the glacier—foreland boundary of an outlet glacier of the Jostedalsbreen ice-cap, southern Norway. Estimates are derived from two types of evidence: (1) the heights of quartz veins...
| Published in: | The Holocene |
|---|---|
| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
SAGE Publications
2007
|
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1177/0959683607081419 http://journals.sagepub.com/doi/pdf/10.1177/0959683607081419 |
| Summary: | Average rates of Holocene chemical weathering and `Little Ice Age' glacial erosion of bedrock are estimated across the glacier—foreland boundary of an outlet glacier of the Jostedalsbreen ice-cap, southern Norway. Estimates are derived from two types of evidence: (1) the heights of quartz veins above adjacent surfaces of granitic or granodioritic gneiss; and (2) Schmidt-hammer R-values of rock hardness. Average and maximum rates of surface lowering of gneiss surfaces by chemical weathering are 1.63 and 3.61 mm/ka, respectively, whereas many quartz veins exhibit negligible weathering after c. 9700 years. `Little Ice Age' glacial erosion rates are at least two orders of magnitude greater than the chemical weathering rates, except in a narrow marginal zone inside, but close to, the `Little Ice Age' limit, where patches of weathered surface survive. Bedrock surfaces outside and well inside the `Little Ice Age' glacier—foreland boundary are shown to have potential for improved calibrated-age dating using R-values, compared with moraine surfaces. |
|---|