Palaeomagnetic Dating of some Younger Dikes in Southern Norway

Abstract

THE occurrence of several localities of younger basic dikes in southern Norway has aroused considerable geological interest in the past. The dikes are especially common in the coastal districts between the Permian Oslo graben and the schists of the Stavanger area. Their absolute age has remained unknown, but a connexion with the Permian igneous activity in the Oslo area has been proposed^1,2. Nevertheless, radioactive dating of younger Norwegian dikes has hitherto not been carried out. On this background a systematic palaeomagnetic study of the younger dikes in Norway has been undertaken by me, assuming it to be a useful tool for absolute as well as relative age determinations. So far only the extensive swarms of dolorites in the anorthosite rock complex in Rogaland have been investigated and in this communication the results are summarized.