Absolute age determinations in East Greenland

Abstract

This report presents a preliminary study of the absolute ages of the rocks of Eastern Greenland conducted in cooperation between the Geo chemistry Laboratory of Columbia University and the East Greenland Expeditions directed by Lauge Koch. The available samples were stored at the University of Basle. These were either hand specimens or chips as they had been collected for petrographic rather than isotopic age studies. As a result only a preliminary survey was possible using the potassium-argon method (CARR and KULP, 1957). The uranium-lead method on zircon will be of great use in future studies but this requires large samples. The most critical samples were selected in a conference of the authors at Basle. The isotopic ages were determined under the direction of J. L. Kulp by R. Kologrivov at Columbia University. J. Haller provided the petrographic descriptions of the samples and the petrologic discussion of the data and its implications for the structural history of the East Greenland Fold Belt.