THE EXPOSURE AGE OF AN EGESEN MORAINE AT JULIER PASS, SWITZERLAND MEASURED WITH THE COSMOGENIC RADIONUCLIDES BE-10, AL-26 AND CL-36

The Egesen moraine complex on the east side of Julier Pass has a mean exposure age of 11,100 years. The exposure age is based on accelerator -mass-spectrometry-measured concentrations of Be-10, Al-26 and Cl-36 i n six different boulders. Three of the boulders lie along the sharp-cr ested outer lateral moraine and have a mean exposure age of 11,800 yea rs. This moraine wall represents the glacier's response to the climati c collapse at the Very beginning of the Younger Dryas. The other three boulders are located along a hummocky boulder band that cross-cuts th e outer moraine along its terminal front. The exposure age of the inne r moraine is 10,400 years.