GEOSCAN, résultats de la recherche


TitreTectonic reactivation of transverse basement structures in the Grenville orogen of SW Quebec, Canada: Insights from gravity and aeromagnetic data
AuteurDufréchou, G; Harris, L B; Corriveau, L
SourcePrecambrian Research vol. 241, 2014 p. 61-84,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120372
Documentpublication en série
Mediapapier; en ligne; numérique
SNRC31G/09; 31G/10; 31G/11; 31G/12; 31G/13; 31G/14; 31G/15; 31G/16; 31J; 31K; 31N; 31O
Lat/Long OENS -78.0000 -74.0000 48.0000 45.5000
Sujetsorogenèse; régions orogéniques; géologie du socle; roches ignées; roches plutoniques; plutons; interprétations géophysiques; interprétation aéromagnétique; interprétations de la pesanteur; Orogène de Grenville ; tectonique; géophysique; Précambrien
Illustrationslocation maps; images; block diagrams
ProgrammeGisements polymétalliques - Zone magmatique du Grand lac de l'Ours (T.N-O.), GEM : La géocartographie de l'énergie et des minéraux
Diffusé2013 12 06
Résumé(disponible en anglais seulement)
NW-SE trending, transverse lineaments, including the lithospheric-scale Mont-Laurier lineament, are interpreted from regional Bouguer gravity of the Grenville orogen of SW Quebec and adjacent Superior Craton in southeastern Canada. These lineaments, transverse to the ENE trending Grenville orogen, are inferred to correspond to Palaeoproterozoic structures in Archaean basement that have played an important role: (i) in the development of volcano-sedimentary back-arc basins along this segment of the Laurentian margin; (ii) on the geometry of thrust sheets and folds formed during thrusting in the ca.1.23-1.2 Ga Elzevirian orogeny and incorporation of the basins within the orogen; (iii) on reorientation of early-formed structures in the Central Metasedimentary Belt of Quebec (CMB-Q) during ca. 1.19-1.17 Gapost-Elzevirian orogenic collapse; and (iv) for development of syn-plutonic deformation corridors and shear zones at the onset of the emplacement of the Morin anorthosite-mangerite-charnockite-granite(AMCG) suite. In the CMB-Q, a 100 km wide megakink zone developed during ca. 1.19-1.17 Ga differential, post-Elzevirian orogenic collapse in the upper-most nappe above transverse sinistral shear corridors10-20 km wide located in an underlying thrust sheet or “lower-deck”. Emplacement of 1.17 Ga Chevreuil intrusive suite preferentially occurred within the megakink zone, starting late in the post-Elzevirian col-lapse and culminating during a switch to local shortening early in (and in part as a consequence of)the emplacement of the voluminous Morin anorthosite and associated AMCG-suite plutons. The Labelle deformation zone separating the CMB-Q and Morin terrane is interpreted as a post-Shawinigan, reverse shear zone that truncates folded lithological layering in the eastern CMB-Q and western Morin terrane that is either subsequently folded above the Mont-Laurier lineament during its further reactivation, or developed as a curved shear zone stepping across the Mont-Laurier lineament. The Grenville Province of SW Quebec therefore provides an example of strain partitioning and distinct deformation responses at different crustal levels during reactivation of basement structures.