Quaternary glaciations in southern Fennoscandia: evidence from southwestern Norway and the northern North Sea region

Based on records from the northern North Sea and southern Norway, Quaternar y Fennoscandian glaciations are described and discussed. Maximum glaciation , defined as the presence of shelf edge glaciation, an ice stream flowing o ut of the Norwegian Channel and most likely an ice divide over the central part of Fennoscandia (Sweden, Gulf of Bothnia), occurred for the first time in the late Cenozoic at ca. 1.1 myr (the Fedje Glaciation). This glaciatio n was followed by a ca. 600 kyr period with at least two glaciations with i ce extension somewhat larger than the Younger Dryas event in the region. Th e first maximum glaciation of the Bruhnes Chron was during isotope stage 12 and was followed by repeated maximum glaciations within each of the light isotopic stages until stage 2. During the Weichselian. the southwestern par t of the Fennoscandian ice sheet reached maximum position three times (some time between 22 and 28, 37 and 50, and 60 and 80 ka). Limited glaciations p robably occurred during stadials between the early and middle Weichselian i nterstadials, between 500 ka and 1.1 Myr, and most likely also prior to 1.1 Myr. Deep Norwegian Sea Ice Rafted Detritus (IRD) records, reflecting cont ributions from several different ice sheets (Fennoscandian, Barents Sea, Ic eland and Greenland), each with large variations in history of ice extent t o their respective margins, yet to some degree they reflect the glaciation of the northern North Sea region with an increasing IRD input around 1.1 My r and a relatively low input of North Sea components, during some cycles ar ound the B/M boundary. Maximum glaciations occurred during insolation minim a in the earlier part of the Middle Pleistocene, however, not all such mini ma are reflected by maxim um glaciation in southern parts of Fennoscandia. The relatively poor chronological control and non-continuous character of t he data on Weichselian interstadials/stadials precludes a clear relationshi p to atmospheric changes recorded in Greenland ice cores, as well as to pre cession and/or obliquity cycles in insolation. (C) 2000 Elsevier Science Lt d. All rights reserved.