Cirque glacier activity in arctic Norway during the last deglaciation

Abstract

AbstractNumerous cirques of the Lofoten–Vesterålen archipelago in northern Norway have distinct moraine sequences that previously have been assigned to the Allerød-Younger Dryas (∼ 13,400 to 11,700 yr BP) interval, constraining the regional distribution of the equilibrium-line altitude (ELA) of cirque and valley glaciers. Here we present evidence from a once glacier-fed lake on southern Andøya that contests this view. Analyses of radiocarbon dated lacustrine sediments including rock magnetic parameters, grain size, organic matter, dry bulk density and visual interpretation suggest that no glacier was present in the low-lying cirque during the Younger Dryas-Allerød. The initiation of the glacial retreat commenced with the onset of the Bølling warming (∼ 14,700 yr BP) and was completed by the onset of Allerød Interstade (∼ 13,400 yr BP). The reconstructed glacier stages of the investigated cirque coincide with a cool and dry period from ∼ 17,500 to 14,700 yr BP and a somewhat larger Last Glacial Maximum (LGM) advance possibly occurring between ∼ 21,050 and 19,100 yr BP.