Moraine exposure dates imply synchronous Younger Dryas glacier advances inthe European Alps and in the Southern Alps of New Zealand

Samples taken from the top surfaces of boulders on the Lake Misery moraines at Arthur's Pass, in the Southern Alps of New Zealand, were analysed for B e-10 by accelerator mass spectrometry. Exposure ages calculated with the cu rrently accepted production rate, along with scaling corrections for sample latitude and elevation (42 degrees 50'S, 960 m), are: 9300 +/- 990, 11,000 +/- 1360, 11,410 +/- 1030, 12,050 +/- 960, and 12,410 +/- 1180 years. We c onsider the date of 9300 years to be an outlier, not included in our mean e xposure age of 11,720 +/- 320 years for the Lake Misery moraines. Based on exposure ages and geomorphologic similarities, we compare the Lake Misery m oraines with an Egesen moraine complex at Julier Pass in the Swiss Alps (46 degrees 30'N, 2200 m). Based on the Be-10,Al-26,and Cl-36 exposure ages of three boulders, we calculate a mean exposure age of 11;750 +/- 140 years f or the outer Egesen moraine at Julier Pass. Based solely on 10Be measuremen ts, we obtain a mean exposure age of 11,860 +/- 210 years for this outer mo raine. Egesen moraines in the Swiss Alps represent glacier readvance during the Younger Dryas cold reversal, based on regional correlations and on bas al radiocarbon dates from bogs located up-valley of Egesen moraines. The ex posure dates from Arthur's Pass and Julier Pass show synchronous glacier ad vances both in the Southern Alps and in the European Alps during the Europe an Younger Dryas chronozone of Mangerud et al.