The central granitic stock within the Glitrevann cauldron comprises three main granite types, of which the youngest one, an aplitic granite, is associated with significant porphyry-Mo mineralizations. A mineralogical and geochemical differentiation is developed from the older granite types towards this aplitic granite. Quantitative trace element modelling, based on crystal fraction using petrographic mixing calculations relating three main compositions, suggests that the aplitic granite represents a fractionated residual melt, possibly formed during progressive volatile-pressure relief. Molybdenum entered the escaping fluid phase, giving rise to the mineralizations.
Geochemistry of the central granitic stock in the Glitrevann cauldron within the Oslo rift, Norway