Late Holocene climate change in central Sweden inferred from lacustrine stable isotope data
(English)In: Journal of Quaternary Science, ISSN 0267-8179Article in journal (Other academic) Submitted
Stable isotopes (18O and 13C) of lacustrine carbonates (Chara spp algae and Pisidium spp molluscs) from a lake sedimentary sequence in central Sweden were analysed to infer changes in lake hydrology and climate during the late Holocene. Results from analysis of lake water isotopes (18O and 2H) show that Lake Blektjärnen water isotope composition is responsive to the water balance between evaporation and input water (E/I ratio). A high E/I ratio results from a dry and probably warmer climate, decreasing the relative importance of precipitation input. Under such conditions evaporation and atmospheric equilibration enrich lake water in 18O and 13C, respectively, which is reflected in the isotopic composition of the carbonates in the lake. From the relatively positive Chara 18O values we infer that conditions were dry and warm between 4400-4000 cal yr BP whereas more negative values indicate that conditions were wetter and probably cooler between 4000-3000 cal yr BP. A drier climate is inferred from more positive values between 2500-1000 cal yr BP. However, a successive depletion after ca 1750 cal yr BP, also detected in several other 18O records (carbonate and diatom), suggest increasingly wetter conditions in Scandinavia after that time, which is probably related to increased zonal flow.
stable isotopes, Chara spp, Pisidium spp, lake hydrology, humidity, central Sweden, late Holocene
Research subject Quarternary Geology
IdentifiersURN: urn:nbn:se:su:diva-36877OAI: oai:DiVA.org:su-36877DiVA: diva2:290866