A LONG-TERM PERSPECTIVE ON GLACIAL EROSION

A rough estimate of glacial erosion in the Precambrian basement is rel ated to the total denudation of bedrock since its formation in the Pro terozoic. The basis for the calculations is reference to surfaces of d ifferent age. Glacial erosion is responsible for merely polishing the northern shields. Major denudation occurred during the Proterozoic and amounted to tens of kilometres. During long periods the basement was protected by Palaeozoic cover rocks. It was re-exposed successively du ring the Mesozoic and Tertiary with denudation amounting to 600m at th e most. Glacial erosion can generally be counted in tens of metres tho ugh with great variations. (C) 1997 by John Wiley & Sons, Ltd.