Palaeoseismicity and De Geer moraines

De Geer moraines are small moraine ridges formed partly in crevasses at the base of glacier ice. There may be several different origins of the crevass es. One possibility, proposed by Gerard De Geer who first studied these rid ges, was seismic activity in connection with the isostatic rebound during t he deglaciation. The present study shows a close connection between occurre nces of De Geer moraines in Fennoscandia and seismic activity or fresh-look ing fault lines and other features indicating neotectonic movements. This s upports De Geer's theory but does not exclude formation in crevasses formed in other ways. There is no real proof that the tectonic movements took pla ce in the Quaternary but the close connection between the moraines and tect onic features is evidence pointing in this direction. If this is correct it has important implications for the stability within cratons of Precambrian crystalline bedrock. (C) 2000 Elsevier Science Ltd and INQUA. All rights r eserved.