U-Pb geochronology and geochemistry of trondhjemites and norite pluton from the SW Trondheim Region, Central Norwegian Caledonides
Abstract
Zircon analyses from two trondhjemites and a biotite norite from a part of the southwestern Trondheim Region have yielded almost identical Early Silurian ages. The biotite norite and one of the trondhjemites, from a quarry in the Innset massif in the Støren Nappe, produced analytical data which define concordia ages of 435,8+-0,9 Ma and 434,8+-0.8 Ma. All three dates are interpreted to represent the ages of emplacement of these bodies. (forkortet)