U-Pb zircon dating of felsic intrusions, Middle Koeli Nappes, central Scandinavian Caledonides

U-Pb zircon data are presented for three metamorphosed trondhjemites from the Middle Koeli Nappes in northern Jaemtland and southern Vaesterbotten, Sweden. The analysed zircon fractions give concordant or practically concordant U-Pb ages, defining three distinct age groups, one for each sample. The most precise ages are given by the 206Pb/238U ratios. The experimental procedures employed are described and the constants used in the calculations of ages are listed