40Ar/39Ar geochronological constraints from the southeasternmost part of the Eastern segment of the Sveconorwegian orogen: Implications for timing of granulite-facies metamorphism

The Southwest Swedish Granulite Region is characterized by mafic granulite- and upper amphibolite-facies rocks, charnockites, and deformed and migmatized granitic to intermediate gneisses. A 40Ar/39Ar geochronological study was carried out focusing on the mafic rocks. Three granulites and four amphibolites have been analysed. The obtained ages range between 930 and 1030 Ma. The older 40Ar/39Ar ages are interpreted to be associated with crustal thickening, while the younger 40Ar/39Ar ages may be associated with final orogenic uplift.