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TitreEvidence for early (ca. 1.9 Ga) interaction between the Trans-Hudson orogen and Superior margin in the Pikwitonei - Snow Lake corridor
AuteurPercival, J A; Whalen, J B; Rayner, N
SourceGAC-MAC-CSPG-CSSS Halifax 2005, building bridges - across science, through time, around the world: abstracts/AGC-AMC-SCGP-SCSS Halifax 2005, Jeter des ponts entre les disciplines scientifiques, les époques, et unifier le monde : recueil des résumés; AGC-AMC-SCGP-SCSS Reunion conjoint, Receuil des Résumés vol. 30, 2005 p. 152-153
LiensOnline - En ligne (HTML)
Séries alt.Secteur des sciences de la Terre, Contribution externe 2004316
RéunionEarly to Mid-Proterozoic Crustal and Lithospheric Evolution - The Dawn of Modern-Day Tectonics (GAC Halifax Symposium); Halifax, Nova Scotia; CA; mai 16-18, 2005
Documentpublication en série
SNRC63K/01; 63K/10; 63K/11; 63K/12; 63K/13; 63K/14; 63K/15; 63K/16
Lat/Long OENS-102.0000 -100.0000 55.0000 54.5000
Sujetsorogénies; orogenèse; marges continentales; plutons; arcs magmatiques; Archéen; gneiss; levés de reflexion sismiques; métamorphisme; déformation; magmatisme; craton
Résumé(disponible en anglais seulement)
Rifting events (2.1-1.88 Ga) and an oceanic free face characterized most of the northwestern Superior margin until collision with the Trans-Hudson orogen at ca. 1.81 Ga. Significantly older compressional activity is evident along the autochthonous western Superior margin
(AWSM) south of Thompson, where 1.89-1.83 Ga plutons of arc-like hornblende granodiorite cut Archean gneisses, permitting an
interpretation of east-dipping seismic reflections as 1.89-1.83 Ga subduction geometry rather than late vergence reversal. At Setting
Lake to the west, where Superior margin affinity (SMA) is inferred from Nd model ages, isotopically evolved 1.89-1.87 Ga plutons were
juxtaposed with <1.85 Ga sediments of the Burntwood and Grass River groups prior to polyphase deformation and metamorphism.
Relationships are uncertain between this 1.89 Ga continental magmatism (AWSM and SMA) and 1.906-1.885 Ga units of the Trans-
Hudson internides (THI) that include isotopically evolved rocks exposed near Flin Flon (Mystic Lake suite) and juvenile plutonic rocks
in the Snow Lake area (Herblet Lake dome, Rex Lake complex and Namew gneiss complex), that correspond in age to juvenile volcanic
arc production. Our working hypothesis involves creation of the Superior margin ca. 2.07 Ga and autochthonous deposition of the
Ospwagan Group; early (ca. 1.90 Ga) deformation (collision with proto-THI?) and early arc magmatism (1.90-1.885 Ga) on AWSM and
SMA. A sliver of pericratonic material (SMA) was removed during 1.883 Ga rifting and within a few million years was thrust beneath
juvenile Trans-Hudson rocks in an intra-oceanic event. Common ages (1.87-1.83 Ga) of successor arc magmatism that is juvenile in the THI and evolved on AWSM and SMA suggest THI development in a marginal basin prior to ca. 1.83-1.79 Ga collision with AWSM.
Implications for paleogeography, plate interaction and ca. 1.88 Ga rift magmatism are being explored through further geological,
geochronological and geochemical studies.