AN EMPIRICAL MODEL OF SHORE-LEVEL DISPLACEMENT IN FENNOSCANDIA

Shore-level displacement and glacio-isostatic uplift in the area affected by the Scandinavian ice is described within an empirical model. The model is initially based on detailed lake-tilting investigations. Besides this information the model is based on 75 shore-level curves from all over Scandinavia and information concerning present relative uplift recorded by precision levelling and tide gauge data. The course of glacio-isostatic uplift is expressed in mathematical terms without using rheological assumptions, which means that the model can be used for evaluations of both geological and geophysical parameters involved in the glacio-isostatic process.

The model indicates that there have been two components involved in glacio-isostatic uplift. These are called the slow and the fast components. The main uplift, still in progress, acts slowly. During the end of the deglaciation there was a short interval with somewhat faster crustal changes. The two components are calculated mainly from two factors designated the down load factor and the inertia factor. The down load factor represent uplift at the time for the maximal uplift rate, and the inertia factor describes the evolution of uplift in time.

The model is transformed to a GIS -application using levelling data. Maps showing the distribution between land and sea at different times are produced by this application. This GIS –application has been successively improved and gives now the possibility to show changes of the hydrography through time including changes in lakes, glacial lakes, rivers and drainage basins.