Holocene changes in atmospheric circulation recorded in the oxygen-isotope stratigraphy of lacustrine carbonates from northern Sweden

The oxygen-isotope composition of local precipitation (delta(18)O(P)) is reconstructed from carbonate lake-sediment components in a sediment core covering the last 10000 calendar years from Lake Tibetanus, a small, hydrologically open, groundwater-fed take in the Abisko area, northern Sweden. Compar...

Full description

Bibliographic Details
Published in:The Holocene
Main Authors: Hammarlund, Dan, Barnekow, Lena, Birks, HJB, Buchardt, B, Edwards, TWD
Format: Article in Journal/Newspaper
Language:English
Published: SAGE Publications 2002
Subjects:
Geology
pollen-climate transfer functions
lacustrine carbonates
stratigraphy
oxygen-isotope
stable isotopes
palacoclimate
atmospheric circulation
Holocene
northern Sweden
Abisko
Northern Sweden
Online Access:https://lup.lub.lu.se/record/339983
https://doi.org/10.1191/0959683602hl548rp
Description
Summary:The oxygen-isotope composition of local precipitation (delta(18)O(P)) is reconstructed from carbonate lake-sediment components in a sediment core covering the last 10000 calendar years from Lake Tibetanus, a small, hydrologically open, groundwater-fed take in the Abisko area, northern Sweden. Comparison of the delta(18)O(P) history with a pollen-based palaeotemperature record from the same core clearly reveals pronounced deviations from the normally expected temporal delta(18)O(P)-temperature relation (so-called 'Dansgaard relation') that may be a function of changing oceanicity. The transition from relatively moist, maritime conditions in the early Holocene to a much drier climate after 6500 cal. BP is reflected by major changes in forest extent and composition as recorded by pollen and plant macrofossil data. At the time of maximum influence of westerly air-mass circulation (high zonal index) c. 9500 cal. BP, brought about by high summer insolation and enhanced meridional pressure gradients. delta(18)O(P) at Lake Tibetanus was about 2%, higher than would be predicted by the modem isotope-temperature relation, The occurrence of long-term changes in delta(18)O(P)-temperature relations, which are more sensitive measures of palaeoclimate than either delta(18)O(P) or temperature alone, needs to be taken into account when extracting palaeoclimatic information from continental oxygen-isotope records.

Similar Items