OSL dating of Weichselian ice-free periods at Skorgenes, Western Norway

Abstract

During recent years, many sites with sediments pre-dating the Last Glacial Maximum have been identified in formerly glaciated areas. As more and better dates are presented from these sites, the dynamic behaviour of the Scandinavian Ice Sheet is becoming increasingly clear. In this study, we revisited the site Skorgenes in western Norway. Here, sediments from two ice-free periods are found below and interbedded with glacial diamicts. We present an updated chronology for the site, based on ten new Optically Stimulated Luminescence (OSL) dates, and discuss possible correlations. The samples had poor OSL properties but still provide a substantial improvement of the existing chronology. The oldest sediments identified at Skorgenes were deposited in a proglacial subaqueous setting at some point between 21 and 42 ka. This period was followed by a glacial advance and, during the subsequent ice retreat, a delta or subaqueous fan formed at Skorgenes. OSL ages from the foreset beds indicate deposition at some point between 17 and 30 ka, implying that the ice-front retreated east of Skorgenes at least once during the Late Weichselian. A substantial ice advance followed this retreat. The youngest sediments, forming a proglacial delta succession, were deposited during the final deglaciation of the site.