Structural evolution and U-Pb geochronology of the metasedimentary Nemiscau subprovince, Canada: implications for Archean tectonics in the Superior Province

Abstract

The Nemiscau subprovince is a metasedimentary rocks-dominated sequence of the eastern Archean Superior Province. Previous structural and metamorphic studies suggested that it was the result of subduction-related, accretionary and collisional tectonics with adjacent plutonic terranes during the Kenorean orogeny. This study integrates various sets of structural, metamorphic and U-Pb geochronological data suggesting a long-lasting tectonometamorphic evolution between ca. 2843 and 2598 Ma. A non-uniformitarian tectonic model for the Archean more adequately accounts for synchronous vertical and horizontal tectonism as preserved in the Nemiscau basin.