Millennial-scale deglaciation across the European Alps at the transition between the Younger Dryas and the Early Holocene - evidence from a new cosmogenic nuclide chronology

摘要

Reconstructing the spatial and temporal response of mountain glaciers to rapid climate change in the past provides access to the effects of current climate change. Yet, the spatial and temporal variability of past glacier fluctuations is not fully understood. In this study, we focus on the timing of glacier fluctuations in the European Alps during the Younger Dryas/Early Holocene (YD/EH) transition. In an effort to elucidate whether glacier fluctuations were synchronous during this period, we present a new chronology of the Alpine Talefre glacier, based on 14 new Be-10 ages of moraines and roches moutonnees. The retreat of Talefre glacier was initiated during the mid-YD (similar to 12.4 ka), then it experienced a gradual retreat punctuated by at least three oscillations until similar to 11 ka before shrinking substantially within its Little Ice Age limits (13th-19th centuries). Comparison of our findings with published glacier chronologies in the Alpine region highlights broadly synchronous behaviour of glaciers across the Alps between 12 and 10 ka. The coeval glacier fluctuations at a regional scale suggest that common regional climate conditions had a major impact on Alpine glacier variations during the YD/EH transition. The similarity of glacier behaviour and independent temperature records in both the Alpine region and the northern high latitudes suggests a teleconnection between these regions, but differences in the amplitude of the mean annual temperature signals relative to summer temperature indicate pronounced changes in seasonality between the YD and the EH.