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TitrePaleoproterozoic crustal evolution and tectonic processes: insights from the LITHOPROBE program in the Trans-Hudson Orogen, Canada
AuteurCorrigan, D
SourceTectonic styles in Canada: The LITHOPROBE perspective; par Percival, J A (éd.); Cook, F A (éd.); Clowes, R M (éd.); Geological Association of Canada, Special Paper 49, 2012 p. 237-284
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120003
ÉditeurAssociation géologique du Canada
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceTerre-Neuve-et-Labrador; Nunavut; Québec; Ontario; Manitoba; Saskatchewan; Territoires du Nord-Ouest
SNRC64; 74; 54; 44; 45; 55; 65; 35; 25; 24; 26; 36; 37; 46; 47; 56; 66
Lat/Long OENS-116.0000 -60.0000 71.0000 56.0000
Sujetséléments tectoniques; modèles tectoniques; évolution tectonique; cadre tectonique; interprétations tectoniques; orogenèse; Orogène de Trans-hudson ; tectonique; Précambrien; Protérozoïque
ProgrammeGisements polymétalliques - Presqu'île Melville (Nunavut), GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
The Trans-Hudson Orogen of North America is one of the earliest orogens in Earth's history that evolved through a complete Wilson-Cycle. It represents approximately 150 million years of opening of the Manikewan Ocean, from ca. 2.07 to 1.92 Ga, followed by its demise in the interval 1.92 - 1.80 Ga, during the final phase of growth of the Supercontinent Nuna and eventual formation of Laurentia. It is a composite orogen, in the sense that it contains numerous juvenile to partly contaminated oceanic arc terranes, oceanic crust, as well as ribbon micro-continents and smaller Archean crustal fragments that were accreted prior to terminal collision with the Superior Craton, with each major accretion event forming its distinct orogeny. Overall, the Trans-Hudson Orogen comprises a large internide region dominated by juvenile crust (Reindeer Zone), bound to the north and south by variably reactivated Archean crust of the i) Western Churchill Province and ii) Superior Boundary Zone, respectively. Accretion appears to have nucleated early, at ca. 1.90 Ga on the SE margin of the Rae Craton, and progressed in that direction until final closure of the Manikewan Ocean and docking of the Superior Craton (terminal collision) during the interval ca. 1.83 to 1.89 Ga. In terms of rate, scale, style and duration of tectonic and crust formation processes, the Trans-Hudson Orogen contains all the hallmarks of modern orogens dominated by accretion and collision, such as the Appalachian and Alpine-Himalayan systems, for example. These include passive margin development, formation of intraoceanic and continental margin arcs and back-arcs, ophiolite formation and obduction, thrust stacking, crustal thickening and development of orogenic pro-wedge and retro-wedge. Lithospheric scale processes such as slab breakoff and hinge roll-back are also suspected to have operated. With the above observations, it can be assumed that the rheology, composition and thermal structure of the lithosphere had evolved to conditions similar to those observed today approximately 2.5 Ga after formation of Earth, during the Paleoproterozoic. Notable absentees in terms of process are the formation of core complexes, large-scale extensional faults, and lower crustal flow. However, their absence from the Trans-Hudson and other Paleoproterozoic orogens in Canada may not signify that these processes did not operate at that time, but perhaps that they simply have yet to be recognized.