North Atlantic region atmospheric circulation dynamics inferred from a late-Holocene lacustrine carbonate isotope record, northern Swedish Lapland
The first high-resolution record of climate variation based on the oxygen and carbon isotope composition of authigenic carbonate for northern Scandinavia is presented. Modern lake-water isotope data indicate that controls on its oxygen and hydrogen (δ 18 O w and δD w ) composition are unlikely to be...
| Published in: | The Holocene |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
SAGE Publications
2007
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1177/0959683607080508 http://journals.sagepub.com/doi/pdf/10.1177/0959683607080508 |
| Summary: | The first high-resolution record of climate variation based on the oxygen and carbon isotope composition of authigenic carbonate for northern Scandinavia is presented. Modern lake-water isotope data indicate that controls on its oxygen and hydrogen (δ 18 O w and δD w ) composition are unlikely to be evaporation or temperature, and its variations must therefore reflect changes in, or at the source of, precipitation. Substantial and persistent changes of the isotopic composition of the precipitation are required to change the mean annual isotope composition of lake surface water. For this reason we argue that the recorded changes were significant and that the recurrence of such changes would greatly affect future regional climate conditions in the North Atlantic region. Oxygen isotope (δ 18 O) minima occurring at ∼ 200, 500, 1300, 1600 and at 2900 cal. yr BP all coincide with major peaks in North Atlantic ice rafted debris deposition. We suggest that the depletion events in δ 18 O cycles recorded in several lakes in northern Swedish Lapland are caused by the same climatic shifts as those noted in the North Atlantic marine records. This is because changes of atmospheric circulation pattern and the lower ocean and atmospheric temperatures associated with the IRD events help to explain why 18 O depletion of precipitation occurred during these events. Our findings indicate that the recorded changes in North Atlantic ice drift and surface hydrography are coupled to changes in atmospheric circulation. |
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