Pleistocene stratigraphy in the Dellen region, central Sweden
1997 (English)In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 26, 237-260 p.Article in journal (Refereed) Published
The Pleistocene stratigraphy in the Dellen region, central Sweden was studied using field observations made during mapping of Quaternary deposits and fabric analyses in excavated sections. The lithostratigraphy was also studied by seismic refraction measurements, analyses of grain-size distribution and organic carbon content. Biostratigraphical methods applied were pollen and diatom analyses. A general outline of the Pleistocene stratigraphy in the area is presented. Three different till beds are identified, the lowermost suggested to have been deposited during the Saalian glaciation and the other two during the Weichselian glaciation. According to the interpretation of the stratigraphy, it is questioned whether the first Weichselian ice sheer did in fact reach the Dellen area. A clayey sediment sequence at Norra Sannas accumulated during an interglacial, probably the Eemian. Most of the interglacial vegetation succession is reflected in the identified pollen flora. An initial phase with a light-demanding forest of Betula and Pinus was followed by immigration of Alnus, Picea and scattered occurrences of Corylus. A freshwater diatom flora was identified dominated by plankton taxa, e.g. Aulacoseira italica, A. distans and Cyclotella spp. In the lower part of the sequence a brackish-marine flora was registered, representing accumulation in a bay of the Eemian Sea. Fine-grained sediments at the Sundson and Vastansjo sites are interpreted as rebedded Eemiar. sediments according to the pollen flora. An (Early Weichselian) interstadial age is suggested ibr sediments found at Bjuraker. Dating by the C-14- and OSL methods was carried out on the interglacial and interstadial sediments, respectively. The ages range from approximately 19 000 to 92 000 BP. Correlation of interglacial vegetation history with central Finland and other areas is discussed.
Place, publisher, year, edition, pages
1997. Vol. 26, 237-260 p.
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:sh:diva-5977DOI: 10.1111/j.1502-3885.1997.tb00854.xOAI: oai:DiVA.org:sh-5977DiVA: diva2:394772