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TitrePaleoproterozoic orogenesis during Nuna aggregation: a case study of reworking of the Rae craton, Woodburn Lake, Nunavut
AuteurPehrsson, S J; Berman, R G; Davis, W J
SourcePrecambrian Research vol. 232, 2013 p. 167-188, https://doi.org/10.1016/j.precamres.2013.02.010
Année2013
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130007
ÉditeurElsevier
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1016/j.precamres.2013.02.010
Mediapapier; en ligne; numérique
Formatspdf
ProvinceNunavut; Québec; Région extracotière; Territoires du Nord-Ouest; Manitoba; Saskatchewan; Alberta
SNRC16C; 16D; 16E; 16F; 16K; 16L; 16M; 16N; 23M; 23N/04; 23N/05; 23N/06; 23N/11; 23N/12; 23N/13; 23N/14; 24C/02; 24C/03; 24C/04; 24C/05; 24C/06; 24C/07; 24C/08; 24C/09; 24C/10; 24C/11; 24C/12; 24C/13; 24C/14; 24C/15; 24C/16; 24D; 24E; 24F; 24G/04; 24G/05; 24G/06; 24G/10; 24G/11; 24G/12; 24G/13; 24G/14; 24G/15; 24I/05; 24I/12; 24I/13; 24J; 24K; 24L; 24M; 24N; 24O; 24P/03; 24P/04; 24P/05; 24P/06; 24P/07; 24P/09; 24P/10; 24P/11; 24P/12; 24P/13; 24P/14; 24P/15; 24P/16; 25; 26; 27; 33M; 33N; 33O; 33P; 34; 35; 36; 37; 38A; 38B; 38C; 38D; 43M; 43N; 43O; 43P; 44; 45; 46; 47; 48A; 48B; 48C; 48D; 53M; 53N; 53O; 53P; 54; 55; 56; 57; 58A; 58B; 58C; 58D; 63M; 63N; 63O; 63P; 64; 65; 66; 67; 68A; 68B; 68C; 68D; 73M; 73N; 73O; 73P; 74; 75; 76; 77; 78A; 78B; 78C; 78D; 83M; 83N; 83O; 83P; 84; 85; 86; 87; 88A; 88B/01; 88B/02; 88B/03; 88B/04; 88B/05; 88B/06; 88B/07; 88B/08; 88B/09; 88B/10; 88B/11; 88B/15; 88B/16; 88D/03; 88D/04; 88D/05; 88D/06
Lat/Long OENS-120.0000 -60.0000 74.0000 55.0000
Sujetsanalyse structurale; Orogène de Trans-hudson ; Géochronologie; géologie structurale
Illustrationslocation maps; geological sketch maps; tables; photographs; diagrams; Concordia diagrams
ProgrammeUranium, GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
New insights into the assembly of the Nuna supercontinent are gained from detailed mapping, structural analysis, and geochronology which constrain the tectonometamorphic evolution of the Rae craton,Woodburn Lake area, Nunavut. The earliest Paleoproterozoic fabric, SP1, is a subhorizontal to shallowly dipping schistosity that helps to define a regional fold and thrust belt bracketed in age between 1.95 and1.83 Ga. The probable ca. 1.9 Ga age and southerly vergence of this belt are consistent with formation during the 1.9 Ga collision of the Rae and Hearne cratons.The other dominant regional fabric, SP2, is related to a northwest-vergent, thick-skinned, fold-thrustbelt involving Paleoproterozoic cover and Archean basement. In situ SHRIMP monazite data for three amphibolite-facies metasedimentary samples yield statistically indistinguishable ages regardless of textural location, most precisely dated at 1834 ± 5 Ma from monazite inclusions in garnet that are aligned with the external SP2 foliation. The chemical and textural features suggest synchronous, syn-DP2 monazite and garnet growth at 540-560 C on a clockwise P-T path constrained by thermobarometry and calculated phase relationships. The extent, orientation and vergence of the tectonic thickening event indicated by these observations is most consistent with the ca. 1870 Ma collision of Meta Incognita-Sugluk block with the southeastern flank of the Rae craton, during early stages of Manikewan ocean closure. Three subsequent phases of deformation are related to final stages of amalgamation of Nuna. The widespread extent, yet contrasting times, of mid-Paleoproterozoic interior orogenic reworking recognized within the western Churchill Province negates the use of its interior Trans-Hudson-related orogens as piercing points for Nuna reconstruction.
Résumé(Résumé en langage clair et simple, non publié)
On a étudié l'historique des roches précambriennes dans les environs de Woodburn Lake au Nunavut afin de déterminer à quel moment les principaux plissements et failles, et le métamorphisme se sont produits. Grâce à la réalisation de cartes, d'une étude structurale et de l'analyse en laboratoire de minéraux métamorphiques, on a pu établir que les principaux événements qui ont façonné ces roches remontent à près de 1,9 milliard d'années, soit au moment où le premier supercontinent terrestre était en cours d¿assemblage. Il existe un lien entre l'ordre des cycles de formation et la nature des plissements et des chevauchements, et la forme des blocs qui sont entrés en collision les uns avec les autres pendant cette période d'assemblage. Cette histoire tectonique est comparable à celle du craton de l'Australie septentrionale.
GEOSCAN ID292507