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TitreElectrical resistivity structure of the Great Slave Lake shear zone, northwest Canada: implications for tectonic history
AuteurYin, Y; Unsworth, M; Liddell, M; Pana, D; Craven, J A
SourceGeophysical Journal International vol. 199, 2014 p. 178-199, https://doi.org/10.1093/gji/ggu251
Année2014
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130465
ÉditeurOxford Academic
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1093/gji/ggu251
Mediapapier; en ligne; numérique
Formatspdf
ProvinceNunavut; Territoires du Nord-Ouest; Alberta; Colombie-Britannique; Saskatchewan
SNRC73M; 73N; 73O; 73P/03; 73P/04; 73P/05; 73P/06; 73P/11; 73P/12; 73P/13; 73P/14; 74A/03; 74A/04; 74A/05; 74A/06; 74A/11; 74A/12; 74A/13; 74A/14; 74B; 74C; 74D; 74E; 74F; 74G; 74H/03; 74H/04; 74H/05; 74H/06; 74H/11; 74H/12; 74H/13; 74H/14; 74I/03; 74I/04; 74I/05; 74I/06; 74I/11; 74I/12; 74I/13; 74I/14; 74J; 74K; 74L; 74M; 74N; 74O; 74P/03; 74P/04; 74P/05; 74P/06; 74P/11; 74P/12; 74P/13; 74P/14; 75A/03; 75A/04; 75A/05; 75A/06; 75A/11; 75A/12; 75A/13; 75A/14; 75B; 75C; 75D; 75E; 75F; 75G; 75H/03; 75H/04; 75H/05; 75H/06; 75H/11; 75H/12; 75H/13; 75H/14; 75I/03; 75I/04; 75I/05; 75I/06; 75I/11; 75I/12; 75I/13; 75I/14; 75J; 75K; 75L; 75M; 75N; 75O; 75P/03; 75P/04; 75P/05; 75P/06; 75P/11; 75P/12; 75P/13; 75P/14; 76A/03; 76A/04; 76A/05; 76A/06; 76A/11; 76A/12; 76A/13; 76A/14; 76B; 76C; 73D; 76E; 76F; 76G; 76H/03; 76H/04; 76H/05; 76H/06; 76H/11; 76H/12; 76H/13; 76H/14; 76I/03; 76I/04; 76I/05; 76I/06; 76I/11; 76I/12; 76I/13; 76I/14; 76J; 76K; 76L; 76M; 76N; 76O; 76P/03; 76P/04; 76P/05; 76P/06; 76P/11; 76P/12; 76P/13; 76P/14; 83M; 83N; 83O; 83P; 84; 85; 86; 93P; 94A; 94H; 94I; 94P; 95A; 95H; 95I; 95P; 96A; 96H; 96I; 96P
Lat/Long OENS-122.0000 -105.0000 68.0000 55.0000
Sujetsévolution tectonique; milieux tectoniques; interprétations tectoniques; antécédents tectoniques; propriétés électriques; Zone de cisaillement de Great Slave Lake ; tectonique
Illustrationslocation maps; sections
ProgrammeDiamands, GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Three magnetotelluric (MT) profiles in northwestern Canada cross the central and western segments of Great Slave Lake shear zone (GSLsz), a continental scale strike-slip structure active during the Slave-Rae collision in the Proterozoic. Dimensionality analysis indicates that (i) the resistivity structure is approximately 2-D with a geoelectric strike direction close to the dominant geological strike of N45?E and that (ii) electrical anisotropy may be present in the crust beneath the two southernmost profiles. Isotropic and anisotropic 2-D inversion and isotropic 3-D inversions show different resistivity structures on different segments of the shear zone. The GSLsz is imaged as a high resistivity zone (>5000 m) that is at least 20 km wide and extends to a depth of at least 50 km on the northern profile. On the southern two profiles, the resistive zone is confined to the upper crust and pierces an east-dipping crustal conductor. Inversions show that this dipping conductor may be anisotropic, likely caused by conductive materials filling a network of fractures with a preferred spatial orientation. These conductive regions would have been disrupted by strike-slip, ductile deformation on the GSLsz that formed granulite to greenschist facies mylonite belts. The pre-dominantly granulite facies mylonites are resistive and explain why the GSLsz appears as a resistive structure piercing the east-dipping anisotropic layer. The absence of a dipping anisotropic/conductive layer on the northern MT profile, located on the central segment of the GSLsz, is consistent with the lack of subduction at this location as predicted by geological and tectonic models.
Résumé(Résumé en langage clair et simple, non publié)
Cet article présente une étude magnétotellurique de la zone de cisaillement du Grand lac des Esclaves, une frontière tectonique importante dans l'ouest du Bouclier canadien. Trois transects géophysiques donnent une image de la structure profonde (jusqu'à 50 km) et apportent des contraintes sur l'histoire géologique. Nous interprétons les résultats pour montrer un changement dans le style tectonique entre la collision précoce des plaques des Esclaves et Rae et le déplacement ultérieur en coulissement.
GEOSCAN ID293671