U-Pb and Rb-Sr isotopic data on an Ordovician, volcanic subvolcanic complex from the Tjopasi Group, Koeli Nappes, Swedish Caledonides

U-Pb and Rb-Sr whole-rock isotopic data for an albite trondhjemite in northernmost Jaemtland, Swedish Caledonides, are presented. Four zircon fractions, three of them almost concordant, define a discordia line with the upper intercept age 488+-5Ma. This age which is considered to date the volcanic-subvolcanic complex, is consistent with the inferred stratigraphical age. The Rb-Sr system in the rock has been disturbed, probably during predeformational alteration (spilitization), and does not provide any chronological informationa. (Authors)