A compilation of K/Ar age determinations on rocks from Greenland carried out in 1969

Abstract

In order to relieve the pressure of routine work on the age dating laboratories in the University of Copenhagen and other institutes working in collaboration with GGU, it was decided to send out samples for K/Ar age determination by a firm of consultants. The problems selected for study were generally of a regional character - for example the basic dyke chronology from SW Greenland - or were preliminary studies of rocks from areas where little isotopic age work had been carried out previously. Much of the material used was far from ideal for accurate determination of a particular event, the selection of samples having been controlled by geological criteria rather than the suitability for precise isotope measurement. The results are therefore to be regarded as pointers for future detailed studies rather than as having given definitive answers. Several of the determinations show the presence of excess argon, sometimes in considerable amounts. The possible geological implications of this are discussed briefly at the end of this note. The ages quoted are averages based on several determinations on each sample.