Unravelling the effective elastic thickness of the Barents Sea
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- Rapporter 
The Barents Sea area is characterised by deep sedimentary basins and a relatively flat-lying crust-mantle interface. The load of such sedimentary basins is generally compensated by the strength of the crust and lithosphere. A parameterisation of this strangth can be obtained by considering the effective elastic thickness. I evaluate the effective elastic thickness of the Barents Sea region by forward calculation of lithospheric flexure under the loads of sedimentary layers and water. The effective elastic thickness is calculated along two profiles from south of Svalbard to Novaya Zemlya. I consider the following compensation mechanisms: 1) local compensation by Airy isostasy, 2) flexure of an elastic plate and 3) flexure of crust and lithisphere with a depth-dependent rheology. The results show that the present-day loads of water and sediments in the Barents Sea region are almost entirely compensated by local Airy isostasy or a very thin elastic plate. The crust of the Barent Sea is therefore weak from an isostatic point of view. The difference in width and depth of sedimentary basins between the western and eastern Barents Sea is not reflected in a difference in effective elastic thickness. I also find that lateral variations in effective elastic thickness are not needed to explain the main features of the basement deflection. This conclusion contrasts with Wienecke et al. (2007) who show low values for elastic thickness in the western Barents Sea and high values throughout the middle and eastern Barent Sea. Their high values may be a result of additional loads that were erroneaously assigned to the crust which require a higher plate strength for compensation. I show that the Wienecke et al. (2007) solution is too stiff and that their effective elastic thickness leads to a poorer fit to basement deflection than obtained in this report.