Tectonic evolution of the western Superior Province from NATMAP and Lithoprobe studies

• Published in: Canadian journal of earth sciences Vol. 43; no. 7; pp. 1085 - 1117
• Main Authors: Percival, John A, Sanborn-Barrie, M, Skulski, T, Stott, G. M, Helmstaedt, H, White, D. J
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada National Research Council of Canada 01.07.2006; NRC Research Press
• Subjects: Abitibi Belt; accretion; Archean; Canada; Canadian Shield; continental crust; crust; Eastern Canada; geophysical methods; geophysical profiles; geophysical surveys; Lithoprobe; Manitoba; metamorphism; NATMAP; North America; North Caribou Terrane; Ontario; Origin; orogeny; plate tectonics; Precambrian; Quetico Belt; review; seismic methods; seismic profiles; Structural geology; Superior Province; surveys; tectonics; Tectonics (Geology); terranes; Wabigoon Belt; Wawa Belt; Western Canada; Winnipeg River Terrane; Canada
• ISSN: 0008-4077; 1480-3313
• DOI: 10.1139/e06-062

Five discrete accretionary events assembled fragments of continental and oceanic crust into a coherent Superior craton by 2.60 Ga. They exhibit similar sequences of events at ∼10 million year intervals: cessation of arc magmatism, early deformation, synorogenic sedimentation, sanukitoid magmatism, bulk shortening, regional metamorphism, late transpression, orogenic gold localization, emplacement of crust-derived granites, and postorogenic cooling. The Northern Superior superterrane recorded 3.7-2.75 Ga events prior to 2.72 Ga collision with the 3.0 Ga North Caribou superterrane. Following 2.98 Ga rifting, the Uchi margin of the North Caribou superterrane evolved in an upper plate setting before 2.72-2.70 Ga collision of the <3.4 Ga Winnipeg River terrane, which trapped synorogenic English River turbidites in the collision zone. The Winnipeg River terrane was reworked in 2.75-2.68 Ga magmatic and tectonic events, including the central Superior orogeny (2.71-2.70 Ga) that marks accretion of the juvenile western Wabigoon terrane. In the south, the Wawa-Abitibi terrane evolved in a mainly oceanic setting until Shebandowanian collision with the composite Superior superterrane at 2.695 Ga. Synorogenic Quetico turbidites were trapped in the collision zone. The final accretionary event involved addition of the Minnesota River Valley terrane (MRVT) from the south, and deposition and metamorphism of synorogenic turbidites of the Pontiac terrane during the ∼2.68 Ga Minnesotan orogeny. Seismic reflection and refraction images indicate north-dipping structures, interpreted as a stack of discrete 10-15 km thick terranes. A slab of high-velocity material, possibly representing subcreted oceanic lithosphere, as well as Moho offsets, support a model of progressive accretion through plate-tectonic-like processes.