U-Pb zircon ages of a tonalite and a granodiorite dykefrom the southeastern part of the Bindal Batholith,central Norwegian Caledonides

• Main Authors: Roberts, David, Gromet, L. Peter, Nissen, August L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2006
• Subjects: GRANODIORITT; TONALITT; DATERING; BERGGRUNNSGEOLOGI; Bindal; Harran; Helgeland; Kongsmoen; Namsskogan; Nordland
• Online Access: https://hdl.handle.net/11250/2674168

An elongate tonalite pluton and a c.10 m-thick granodiorite body in the southeastern part of the Bindal Batholithand Helgeland Nappe Complex, Nord-Trøndelag, have yielded U-Pb zircon ages of 429 \u00B12 and 430 \u00B12 Ma, respectively. These dates are interpreted to represent the crystallisation ages of these rocks and supersede pre-viously published Cambrian Rb-Sr whole-rock isochron ages from these very same bodies. The zircon ages reported here are comparable to other published U-Pb emplacement ages for granitoid plutons in the eastern part of the Bindal Batholith. A foliation in parts of the tonalite and granodiorite, and folds affecting this foliation are considered to have formed during the Scandian orogenic event which, in this part of the Helgeland Nappe Complex, is believedto have initiated at the time of termination of calc-alkaline magmatism at around 428 Ma. 56202