Osl ages in central Norway support a mis 2 interstadial (25 20 ka) and a dynamic Scandinavian ice sheet
2012 (English)In: Quaternary Science Reviews, ISSN 0277-3791, Vol. 44, 96-111 p.Article in journal (Refereed) Published
Recent work has suggested that the Scandinavian ice sheet was much more dynamic than previously believed, and its western marine-based margin can provide an analogue to the rapid-paced fluctuations and deglaciation observed at the margins of the Antarctic and Greenland ice sheets. In this study we used a complimentary dating technique, OSL (Optically Stimulated Luminescence dating), to support the existence of the Trofors interstadial in central Norway; an ice-free period that existed from similar to 25 to 20 ka recorded at multiple sites throughout Norway (cf. Andoya interstadial) and that divides the Last Glacial Maximum (LGM) into two stadials. OSL signal component analysis was used to optimize data analysis, and internal (methodological) tests show the results to be of good quality. Both large and small aliquots gave consistent OSL ages (22.3 +/- 1.7 ka, n = 7) for sub-till glaciofluvial/fluvial sediments at the Langsmoen stratigraphic site, and an apparent old age (similar to 100 ka) for a poorly-bleached sample of glaciolacustrine sediment at the nearby stratigraphically-related Flora site. Eight radiocarbon ages of sediment from the Flora site gave consistent ages (20.9 +/- 1.6 cal ka BP) that overlap within 1 sigma with OSL ages from the nearby Langsmoen site. The similarity in age within and between these stratigraphically-related sites and using different geochronological techniques strongly suggests that this area was ice-free around similar to 21 or 22 ka. The existence of the Trofors interstadial along with other interstadials during the Middle and Late Weichselian (MIS 3 and MIS 2) indicates that not only the western margin, but the whole western part of the Scandinavian ice sheet, from the ice divide to the ice margin was very dynamic. These large changes in the ice margin and accompanying drawdown of the ice surface would have affected the eastern part of the ice sheet as well.
Place, publisher, year, edition, pages
2012. Vol. 44, 96-111 p.
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:su:diva-81714DOI: 10.1016/j.quascirev.2010.10.007ISI: 000307202200009OAI: oai:DiVA.org:su-81714DiVA: diva2:563775