Numerical Modeling of the Late Weichselian Svalbard-Barents Sea Ice Sheet

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Abstract
Previous reconstructions of the ice cover of the Svalbard-Barents Sea region during the late Weichselian have ranged from small ice masses on Svalbard to complete inundation of the Barents Shelf region by an ice sheet several kilometers thick. We have used a time-dependent finite-difference numerical model to undertake a new glaciological reconstruction for the Svalbard-Barents Sea Ice Sheet over the last 30,000 yr. The numerical model requires environmental forcing functions in the form of air temperature and precipitation and their behavior with respect to altitude, together with sea-level change and an iceberg calving relation. Ice buildup on Svalbard is calculated to have begun 28,000 yr ago, and maximum dimensions were reached by 20,000 yr ago, covering Svalbard and the northwestern Barents Sea with a center of mass (1.3 km thick) around eastern Svalbard. Decay was complete by about 10,000 yr ago. The margin of the modeled ice sheet at its maximum is in good agreement with observed sea-floor morphological features, but there are discrepancies in timing between the modeled ice sheet decay and (i) a dated meltwater spike in Fram Strait and (ii) the observed rebound curves for Svalbard. An inverse approach was used to predict ice sheet decay, and it was found that increasing the rate of iceberg calving within the model produces a deglaciation some 2000 yr earlier, which is compatible with these two independent datasets. The reconstruction is also compatible with geological evidence on the isostatic response of Bjørnøya, close to the southern limit of the ice sheet, and seismically observed deposits, interpreted to be ice. proximal facies, located in the northwestern Barents Sea. Our time-dependent model reconstructions of the Svalbard-Barents Sea Ice Sheet indicate ice cover over only the northwestern Barents Sea during the late Weichselian, but this does not preclude the presence of ice derived from Fennoscandia and the Kara Sea region elsewhere in the Barents Sea.