Post-Sveconorwegian exhumation and cooling history of the Evje area, southern Setesdal, Central South Norway

Abstract

Fission track (FT) dating of apatite and sphene from monzonitic dyke rocks in a Middle to Late proterozoic intrusion from the Setesdal region, southern Norway, indicates cooling from intrusion temperatures of the surroundings of approxi- mately 250o before 800-600 Ma. Fluid inclusion studies suggest the crustal depth to have been in the order of 4-5 km at the time. Apatite FT results indicate that during the Palaeozoic the rocks which now occur in the southern Setesdal region were subjected to heating above the closing temperature of apatite. Apatite FT-length distributions and fission track ages of nearly 300 Ma indicate that the region had been buried to a depth of more than c.4 km before this time.