COSMOGENIC NUCLIDE EXPOSURE AGES ALONG A VERTICAL TRANSECT IN WESTERNNORWAY - IMPLICATIONS FOR THE HEIGHT OF THE FENNOSCANDIAN ICE-SHEET

Be-10 and Al-26 exposure ages for bedrock samples from a vertical tran sect at Skala, in western Norway, provide new constraints on the histo ry of the Fennoscandian ice sheet. The weathered bedrock surface (auto chthonous block field) mantling the summit of Skala has an exposure ag e of >55 ka, suggesting that this surface formed before the last glaci al maximum (similar to 18 C-14 ka or similar to 21 calendar ka). The b lock field is truncated by a glacial ''trimline'' at 1660 m above sea level, Glaciated bedrock below the trimline has an exposure age of 26- 21 ka; the range depends on assumptions about erosion rate, Ice theref ore receded from this altitude at about the time of the last glacial m aximum. The Be-10 age for bedrock immediately below a second, lower, t rimline at Skala suggests a glacial advance or stillstand at 18-13 ka, consistent with previously documented readvances or stillstands at th e western and southern margins of the ice sheet.