Ice-free intervals continuing into Marine Isotope Stage 3 at Sokli in the central area of the Fennoscandian glaciations

• Published in: Bulletin of the Geological Society of Finland
• Main Authors: K.F. Helmens, P.W. Johansson, M.E. Räsänen, H. Alexanderson, K.O. Eskola
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Society of Finland 2007
• Subjects: glacial geology; sediments; stratigraphy; pollen analysis; paleobotany; climate change; interstadial environment; interglacial environment; chronology; Pleistocene; Sokli; Lapland Province; Finland; Geology; QE1-996.5; Maaselkä; Peräpohjola; Tulppio; Fennoscandian; Lapland
• Online Access: https://doi.org/10.17741/bgsf/79.1.002; https://doaj.org/article/f404f36c92b941819fda0506fddf2439

An unusually long and continuous Late Quaternary sedimentary sequence has been preserved in a sedimentary basin formed in the Sokli Carbonatite Massif in eastern-central Finnish Lapland. A nearly complete sediment recovery from the central Sokli basin combined with palynological results from sediments not earlier recovered and an independent OSL/AMS 14C chronology allow us here to define the Late Quaternary climate-stratigraphy at Sokli and describe in detail the environmental record. Three interstadial intervals of Weichselian age are distinguished that correlate with MIS 5c, 5a and part of MIS 3 in the marine oxygen-isotope record. The interstadials of MIS 5c and 3 age are here defined as the Sokli and Tulppio Interstadials, respectively. The MIS 5a interstadial is correlated with the Maaselkä/Peräpohjola Interstadials of Finnish Lapland, which previously have been tentatively assigned a MIS 5c age. Till beds in the Sokli sequence (deposited during stadials 3–1) correlate to MIS 5b, 4 and 3/2, respectively. Depositional environments and vegetational changes during the ice-free intervals at Sokli are discussed. The Sokli sedimentary sequence indicates significantly less extensive and more variable ice-cover over Finnish Lapland during the Weichselian than has been earlier suggested based on the long-distance correlation of litho- and bio-stratigraphic fragmentary evidence.