| Summary: | Holocene variations in atmospheric circulation in the North Atlantic region have been reconstructed, based on three individual lake sediment studies from sites along the coast of Norway and Svalbard. This thesis contributes with new palaeoclimatic reconstructions revealing variability in wind and precipitation patterns in the northeastern North Atlantic. In Paper I, we present a new record of Holocene glacier variability of Ålfotbreen ice cap in western Norway. By applying a novel approach of calibrating lake sediments with instrumental glacier mass-balance measurements we are able to extend glacier mass-balance variability as reflected in equilibrium-line altitude (ELA) changes for the last 1400 years. Our data suggest that deglaciation of Ålfotbreen occurred ~9700 cal yr BP, and the ice cap was subsequently absent or very small until a short-lived glacier event is seen in the lake sediments ~8200 cal yr BP. The ice cap was most likely completely melted until a new glacier event occurred around ~5300 cal yr BP. Ålfotbreen was thereafter absent (or very small) until the onset of the Neoglacial period ~1400 cal yr BP. The Little Ice Age (LIA) ~650-50 cal yr BP was the largest glacier advance of Ålfotbreen since deglaciation, with a maximum extent at ~400-200 cal yr BP, when the ELA was lowered approximately 200 m relative to today. The late onset of the Neoglacial at Ålfotbreen is suggested to be a result of its low altitude relative to the regional ELA. Further, we apply a known relationship between summer temperature and ELA variations at 10 glaciers in Norway (including Ålfotbreen) to reconstruct winter precipitation during the last 1400 years. In Paper II, we present a lake record from lake Hakluytvatnet at Amsterdamøya island, the northwesternmost island on Svalbard. The lake sediment archive reveals large environmental changes that have taken place at Hakluytvatnet since the Late Glacial, as detected by multi-proxy analyses including physical sediment properties and diatom analysis. A robust chronology has ...
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