The onset of Pleistocene glaciation in the Barents Sea: implications for glacial isostatic adjustment

Abstract

SUMMARY In this paper the effect of a delayed onset of glaciation in the Barents Sea on glacial isostatic adjustment is investigated. The model calculations solve the sea-level equation governing the total mass redistributions associated with the last glaciation cycle on a spherically symmetric, linear, Maxwell viscoelastic earth for two different scenarios for the growth phase of the Barents Sea ice sheet. In the first ice model a linear growing history is used for the Barents Sea ice sheet, which closely relates its development to the build-up of other major Late Pleistocene ice sheets. In the second ice model the accumulation of the Barents Sea ice sheet is restricted to the last 6 ka prior to the last glacial maximum. The calculations predict relative sea levels, present-day radial velocities, and gravity anomalies for the area formerly covered by the Weichselian ice sheet. The results show that observed relative sea levels in the Barents Sea are appropriate for distinguishing between the different glaciation histories. In particular, present-day observables such as the free-air gravity anomaly over the Barents Sea, and the present-day radial velocities are sensitive to changes in the glaciation history on this scale. A palaeobathymetry derived from relative sea-level predictions before the last glacial maximum based on the second ice model essentially agrees with a palaeobathymetry derived by Lambeck (1995). The additional emerged areas provide centres for the build-up of an ice sheet and thus support the theory of Hald, Danielsen & Lorentzen (1990) and Mangerud et al. (1992) that the Barents Sea was an essentially marine environment shortly before the last glacial maximum.