Late Glacial Mountain Glacier culmination in Arctic Norway 14,000 years ago consistent to southern mid-latitudes

Abstract:

The culmination of Scandinavian glaciers during the Late Glacial period (16-11 ka) has been connected to the Younger Dryas stadial (12.9-11.7 ka). Here we present a detailed geomorphic, chronologic and model reconstruction of LG and Holocene fluctuations of Rødhetta Glacier on the Island of Arnøya in Arctic Norway. Our comprehensive Late Glacial through Holocene ¹⁰Be mountain glacier moraine chronology indicates that the Late Glacial culmination occurred 14.1 ka ago, more than 1000 years prior to the onset of the Younger Dryas stadial. The Younger Dryas glacier advances, with an onset around 12.3 ka ago, were significantly smaller in amplitude than the earlier LG culmination, and Rødhetta Glacier slightly retreated through the Younger Dryas stadial with the final culmination 11.5 ka ago. No subsequent culminations took place during the Holocene until the Little Ice Age. Glacier modeling indicates an Equilibrium Line Altitude lowering compared to present-day (695 m a.s.l.) for the Late Glacial moraine sequence of ~220 m, for the Younger Dryas of ~130 m, and for the Little Ice Age of ~80 m. The most likely climate conditions during the moraine formation periods are represented by summer temperature coolings compared to present-day by Late Glacial ~3.2 °C, Younger Dryas ~1.9 °C, and Little Ice Age ~0.8 °C.

We show that this Late Glacial mountain glacier pattern of Arctic glacier culminations and retreat during the Late Glacial period and the Younger Dryas stadial is consistent with updated glacier records in the North Atlantic region. Recent ¹⁰Be moraine chronologies from the southern mid-latitudes are strikingly similar.