Degree of rock surface weathering on fjell summits in northern Finland: implications for the thermal regime of the last ice sheet

Measures of degree of rock surface weathering on three fjell summits in Finnish Lapland provide an independent test of the extent of continuously cold-based ice during the Late Weichselian. The surface hardness of exposed surfaces is compared with that of surfaces that have remained covered and protected from subaerial weathering. Roughness measurements from granite gneiss surfaces are compared with results from similar lithologies that are known to have been eroded during the Late Weichselian. The results suggest that the summits have been covered and actively eroded by warm-based ice and are difficult to reconcile with suggestions that large parts of Fennoscandia have not been glacially abraded since the Early Weichselian.