Age of the Austurhorn intrusion; a net-veined complex in southeastern Iceland

Previous attempts to date the rocks of eastern Iceland by radiometric means have resulted in a considerable scatter in ages. This was probably the result of hydrothermal alteration, affecting the investigated material, particularly lavas, to a varying degree. This study reports the results of a combined Rb-Sr and K-Ar whole-rock investigation of granophyric material from the Austurhorn complex, southeastern Iceland. The Rb-Sr isochron age obtained for four samples is 12.8 ± 5.3 Ma, consistent with the K-Ar ages which average 11.8 Ma.