U-Pb radiometric age of Nunarsuit pegmatite, Greenland: constraints on the timing of Gardar magmatism

A precise U-Pb radiometric age of 1171±5 Ma has been obtained from zircons from a pegmatite in the Nunarsuit (previously spelt Nunarssuit) complex, Gardar Province, South Greenland. This age is slightly older than a corresponding Rb-Sr isochron determination. Since Nunarsuit is believed to be among the youngest Gardar centres, this radiometric age date more closely delimits the end of magmatism in the Gardar rift province. A comparison of our data with other published isotopic work may suggest that Gardar magmatism was a continuous rather than a punctuated process.