Abstract

Swath bathymetry data and one sediment core were used to improve the understanding of the Late Weichselian and Holocene glacier activity in Billefjorden, Svalbard. Grounded ice existed in Billefjorden prior to 11.23 cal ka BP (calendar years before present), depositing a basal till and producing glacial lineations. The glacier front retreated from the central parts to the inner parts of the fjord between c. 11.23 and 11.2 cal ka BP. Annual recessional moraines suggest that this retreat occurred at a rate of up to 170 m a⁻¹. During the early Holocene, the glacier Nordenskiöldbreen was comparatively small and sediment supply to central Billefjorden occurred mainly from the fjord sides. An increase in ice rafting around 7930 cal a BP is ascribed to enhanced sea-ice formation. The activity of Nordenskiöldbreen increased around 5470 cal a BP. Ice rafting was generally low during the past c. 3230 a. This was most likely related to the formation of a more permanent sea-ice cover. Nordenskiöldbreen reached its maximum Holocene extent around AD 1900, generating glacial lineations and depositing a terminal moraine in the inner fjord. Annual recessional moraines were formed during its subsequent retreat. Icebergs from Nordenskiöldbreen generated iceberg ploughmarks during the late Holocene.