Cosmogenic 10Be dating of the Salpausselkä I Moraine in southwestern Finland

Abstract: We determined in situ cosmogenic 10Be ages for nine boulders sampled on the Salpausselkä I (Ss I) Moraine. Previous dating of this moraine indicated that it formed during the Younger Dryas Stadial along the southern margin of the Scandinavian Ice Sheet in southern Finland. Our new exposure ages range from 10.9±1.0 to 13.5±1.2 10Be ka, with an error-weighted mean age of 12.4±0.7 10Be ka. Our results confirm four previous 10Be ages obtained 40km northeast of our sample location. The combined data ) indicate that retreat from the Ss I Moraine occurred at 12.5±0.7 10Be ka, in excellent agreement with an age of 12.1ka for retreat from the Ss I Moraine based on varve chronologies. These results identify the Ss I Moraine as among the best-dated margins associated with Late Quaternary ice sheets. [Copyright &y& Elsevier]