U-Pb zircon evidence for circa 3.1 Ga crust south of the McDonald Fault, northwestern Canadian Shield, Northwest Territories

Abstract

In the Artillery Lake area a 3129 +13/-10 Ma U-Pb (zircon) age from a tonalite gneiss south of the dextral McDonald Fault indicates that rocks of this terrane are distinct from lithologically similar gneisses of the 2.0-1.9 Ga Thelon Tectonic Zone north of the fault. They are considered to be part of a zone of gneisses derived from Paleoarchean to Mesoarchean crust that occurs along the western Churchill Province margin east of the Taltson Magmatic Zone and Thelon Tectonic Zone.