Geology of the Levack gneiss complex, the northern footwall of the Sudbury structure, Ontario

Rocks of the Archean Levack gneiss complex that underlie the northern part of the Sudbury Structure comprise supracrustal and intrusive units that were deformed and metamorphosed under granulite facies conditions in the lower crust during the Archean. They were intruded by late Archean granite of the Cartier batholith and uplifted, either during the late Archean or early Proterozoic, by tectonic or impact processes. They were strongly affected by the shock and thermal metamorphism associated with the Sudbury impact event and probably contributed significantly to the formation of the Sudbury igneous complex and its ores. Structures imaged by seismic reflection profiles in the area are attributed to thrusts or deformation zones that are part of a regional system of south-dipping structures that cut and displace the Sudbury structure.