Late Weichselian glacier retreat in Kongsfjorden, west Spitsbergen, Svalbard

Abstract

The chronology of Late Weichselian to Holocene deglaciation of Kongsfjorden, west Spitsbergen has been reconstructed based on the geomorphic and stratigraphic record of ice retreat, relative sea-level relationships, and 14C dating of associated marine organic materials. The seaward extent of glacial drift and fjord bathymetry constrain a secure reconstruction for the ice sheet near the mouth of the fjord at ca. 13,000 yr B.P., but do not rule out the possibility that more extensive glaciation was achieved earlier during the Late Weichselian. Regional shoreline relations, rates of emergence, and radiocarbon dating of foraminifera deposited just above till indicate that deglaciation occurred in two steps: one beginning during or just prior to the Late Weichselian Marine Limit phase at 13,000–12,000 yr B.P. and another beginning at 10,000–9500 yr B.P. The fjord was completely deglaciated by 9440 ± 130 yr B.P. A period of stable relative sea level began 10,700 yr B.P. and ended between 10,000 and 9500 yr B.P., which we take to indicate renewed glacial loading during the Younger Dryas. Glacier readvance within Kongsfjorden at this time was diminutive, suggesting that most of the Younger Dryas ice-sheet growth was confined to the eastern part of the archipelago and/or to the Barents Shelf. The two-step deglaciation of Kongsfjorden occurred during intervals of accelerated global ice-sheet melting and rapid oceanic and atmospheric warming in more temperate latitudes of the circum-Atlantic region. This coincidence most likely resulted from contemporaneous increases in the poleward transport of oceanic heat.