Age determinations from the Iveland-Evje area, Aust-Agder.
Abstract
A Rb\/Sr isochron age determination on intrusive granite and monzonite from the Iveland-Evje area gave an age of 1038+- 43 m.y. Biotite from the granite dated by the K\/Ar method gave an age of 845+-60 m.y. These values are very similar to other age determinations on intrusive rocks from Southern Norway. The initial Sr87\/Sr86 ratio of the granite and monzonite is very low: 0.7048+-0.0003. The rocks must be genetically related to the Iveland-Evje pegmatites, which are among the latest intrusions within the Sveconorwegian igneous period.