MIS 3 sediment stratigraphy in southern Sweden sheds new light on the complex glacial history and dynamics across southern Scandinavia

Abstract

Recent studies have revealed that areas with sediments pre‐dating the Last Glacial Maximum (LGM) are more common in southern Scandinavia than previously thought. To describe and date these sediments, four deep core drillings were made in the province of Småland and one in the province of Skåne, southern Sweden, and an existing sediment core drilled in the 1960s from western Skåne was re‐examined and re‐dated, all resulting in a total of 22 AMS 14C ages and 19 OSL ages. With some variation, the Småland cores revealed a stratigraphy consisting of two tills separated by proglacial glacifluvial and glaciolacustrine sediments, dated to between 46 and 25 ka BP (Marine Isotope Stage (MIS) 3 to 2). We suggest that these sediments were deposited during the ice retreat of the MIS 3 Ristinge glaciation over southern Scandinavia and the subsequent re‐advance over the area in late MIS 3 and the transition to MIS 2, when the Fennoscandian Ice Sheet advanced towards its LGM marginal positions. This contrasts with the glacial history of southernmost Skåne, where an additional MIS 3 glacial advance through the Baltic Basin is suggested by the occurrence of a till named Allarp Till. New ages from sediments under‐ and overlying this till suggest that it was deposited by the same Baltic ice advance that deposited the Klintholm till in Denmark (Klintholm Advance, c. 34–30 ka).