A study on the Fennoscandian post-glacial rebound as observed by present-day uplift rates and gravity field model GOCO02S

Sjöberg, L. E. and Bagherbandi, M. (2013) A study on the Fennoscandian post-glacial rebound as observed by present-day uplift rates and gravity field model GOCO02S. Acta Geodaetica et Geophysica Hungarica, 48 (1). pp. 317-331. ISSN 2213-5812 (Print) 2213-5820 (Online)

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Abstract

Repeated absolute gravity measurements in Fennoscandia have revealed that the on-going post-glacial rebound can be regarded as a pure viscous flow of mantle mass of density 3390 kg/m 3 towards the central part of the region caused by a gravity/uplift rate of − 0 . 167 μGal/mm. Our model estimates the rebound induced rates of changes of surface gravity and geoid height to have peaks of − 1 . 9 μGal/yr and 1.6 mm/yr, respectively, the former being consistent with absolute gravity observations. The correlation coefficient of the spherical harmonic representations of the geoid height and uplift rate for the spectral windows between degrees 10 and 70 is estimated to − 0 . 99 ± 0 . 006, and the maximum remaining land uplift is estimated to the order of 80 m. Both the (almost) linear increase of relaxation time with degree and the linear relation between geoid height and uplift rate support a model with mass flow in the major part of the mantle and disqualify the model with a flow in a thin channel below the crust. The mean viscosity of the flow in the central uplift region is estimated to 4 × 10 21 Pa s.

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