Age and Petrogenesis of Two Late Archean Magmatic Suites, Northwestern Superior Province, Canada: Zircon U-Pb and Lu-Hf Isotopic Relations

Corfú, Fernando; Stott, G. M.

doi:10.1093/petrology/34.4.817

Cited by 62 publications

(27 citation statements)

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“…Further, Hollings et al (2000) suggested that the Confederation assemblage of the Meen±Dempster belt was generated in a back arc setting. Corfu and Stott (1993) summarised their study by suggesting that the Birch±Uchi Confederation assemblage was erupted into a back arc basin, an interpretation shared by Lesher et al (1986) and Noble (1989). Further, structural evidence indicates that the 2740 Ma plutons of the Pickle Lake belt were intruded into an already deformed and consolidated terrane, suggesting a continental arc setting.…”

Section: Implications and Conclusionmentioning

confidence: 98%

“…There is clear evidence for crustal contamination of some but not all volcanic sequences along the protocontinental margin, in the isotopic, xenocrystic zircon and geochemical signatures (Breaks et al 1986;Thurston et al 1991a;Tomlinson et al 1998;. Numerous researchers have interpreted the Confederation assemblage of the Birch±Uchi belt as a back arc sequence (Lesher et al 1986;Noble 1989;Corfu and Stott 1993;Rogers et al 2000). Further, Hollings et al (2000) suggested that the Confederation assemblage of the Meen±Dempster belt was generated in a back arc setting.…”

Section: Implications and Conclusionmentioning

confidence: 99%

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An Archean arc basalt–Nb-enriched basalt–adakite association: the 2.7 Ga Confederation assemblage of the Birch–Uchi greenstone belt, Superior Province

Hollings

Kerrich

2000

Contrib Mineral Petrol

131

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The Uchi subprovince of the Archean Superior Province is a series of greenstone belts extending 600 km east±west along the southern margin of the North Caribou Terrane protocontinent. The 2.7 Ga Confederation tectonostratigraphic assemblage of the Birch±Uchi greenstone belt, northwest Ontario, is dominated by volcanic suites of ma®c, intermediate and felsic composition. Tholeiitic basalts range compositionally from Mg# 59±26 evolving continuously to greater REE contents (La 2±19 ppm; Th/La pm~1 ), with small negative Nb anomalies. Primitive tholeiites are similar to modern intraoceanic arc basalts, whereas evolved members extend to greater concentrations of Ti, Zr, V, Sc, and Y, and lower Ti/Zr, but higher Ti/Sc and Ti/V ratios characteristic of back arc basalts. Calc-alkaline basalts to dacites are characterised by more fractionated REE (La/Yb n 1±8), high Th/Nb pm ratios and deeper negative Nb anomalies; they plot with modern oceanic arc basalts and some may qualify as high magnesium andesites. The two suites are interpreted as a paired arc±back arc sequence. A third group of Nb-enriched basalts (NEB; Nb 9±18 ppm) extend to extremely high TiO 2 , Ta, P 2 O 5 , Sc and V contents, with strongly fractionated REE and ratios of Nb/Ta and Zr/Hf greater than primitive mantle values whereas Zr/ Sm ratios are lower. The most abundant rhyolitic suite has extremely enriched but¯at trace element patterns and is interpreted as strongly fractionated tholeiitic basalt liquids. A second group are compositionally similar to Cenozoic adakites and Archean high-Al, high-La/Yb n tonalites; they possess Yb £ 0.4 ppm, Y £ 6 ppm and Sc £ 8 ppm, with La/Yb n of 19±30 and Zr/Sm of 50±59. They are interpreted as melts of ocean lithosphere basaltic crust in a hot shallow subduction zone. Adakites are associated with NEB in Cenozoic arcs where there is shallow subduction of young and/or hot ocean lithosphere, often with oblique subduction. Slab melt adakites erupt, or metasomatise sub-arc mantle peridotite to generate an HFSE-enriched source that subsequently melts during induced mantle convection. The Archean adakite±NEB association erupted during development of the tholeiitic to calc-alkaline arc and its associated back arc. Their coexistence in the Confederation assemblage of the Birch±Uchi greenstone belt implies convergent margin processes similar to those in Cenozoic arcs.

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Section: Implications and Conclusionmentioning

confidence: 98%

Section: Implications and Conclusionmentioning

confidence: 99%

An Archean arc basalt–Nb-enriched basalt–adakite association: the 2.7 Ga Confederation assemblage of the Birch–Uchi greenstone belt, Superior Province

Hollings

Kerrich

2000

Contrib Mineral Petrol

131

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“…The oldest age was obtained on abraded parts of a euhedral tip (analysis 23) and the second oldest on a single euhedral prism (24), whereas the youngest one was obtained on a euhedral short prismatic crystal (27). These relations are unlike those observed in classical core-overgrowth cases and suggest mixing of different zircon populations, for example, by wall rock contamination during emplacement (e.g., Corfu and Stott 1993a;Corfu 1996). The age of the youngest analysis would appear to suggest emplacement of the tonalite at 2705 ± 4 Ma, but because of the difficulty in identifying other zircon crystals of the same age in this population we have to consider the alternative possibility that the grain may actually have been enclosed in some hidden potassic vein, and hence may be unrelated to the tonalite.…”

Section: Biotite Tonalite Suite (Table 1; Fig 4)mentioning

confidence: 59%

Age structure and orogenic significance of the Berens River composite batholiths, western Superior Province

Corfú¹,

Stone²

1998

Can. J. Earth Sci.

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The Berens River area of northwestern Ontario is underlain mainly by Archean felsic plutonic rocks, which enclose minor supracrustal and gneissic enclaves and merge with the greenstone-belt-rich Uchi Subprovince to the south. U-Pb geochronology using zircon and monazite shows that the batholiths evolved mainly between 2750 and 2690 Ma by sequential and essentially continuous intrusive activity into an older substratum composed of 3000-2800 Ma volcanic and tonalitic crust. There is a broad, but not strict, compositional transition from early biotite tonalite and hornblende tonalite, progressing with time towards a greater abundance of hornblende granodiorite to granite, and finally to late biotite granite, rare peraluminous granites, and sanukitoid (dioritic, monzodioritic to granitic) plutons. The tonalite suites were predominantly synvolcanic. The late granitic intrusions postdated volcanism, but were largely synchronous with the main compressional events that caused widespread sedimentation, deformation, and metamorphism in other parts of the region. The age patterns and compositional features of the batholiths and the spatial and temporal links between their evolution and those of the supracrustal sequences in the greenstone belts of the region are consistent with mechanisms of magma generation and emplacement at converging plate margins.Résumé : La région de la rivière Berens, dans le nord-ouest de l'Ontario, est formée principalement de roches plutoniques felsiques de l'Archéen avec une faible proportion des enclaves gneissiques et supracrustales, qui sont mêlées avec la ceinture riche en roches vertes de la Sous-province d'Uchi au sud. Les datations U-Pb sur zircon et monazite montrent que les batholites se sont développés surtout entre 2750 et 2690 Ma, essentiellement et en séquences par intrusion continue dans un substratum plus ancien composé d'une croûte volcanique et tholéiitique datée de 3000 à 2800 Ma. On observe grossièrement une composition transitionnelle, toutefois peu perceptible, débutant par la tonalite à biotite et la tonalite à hornblende précoces, progressant dans le temps vers un enrichissement en granodiorite à hornblende et ensuite en granite, et finalement par la formation du granite à biotite tardif et des plutons occasionnels de granites peralumineux et sanukitoïdes (dioritique, monzodioritique à granitique). Les suites de tonalites étaient surtout synvolcaniques. Les intrusions granitiques tardives sont postérieures au volcanisme, mais généralement synchrones avec les principaux événements du régime tectonique compressif qui furent responsables de la sédimentation, de la déformation et du métamorphisme étendus dans les autres parties de la région. Les diagrammes des âges, les particularités des compositions des batholites, et les relations temps-espace entre leur évolution et celles des séquences supracrustales dans les ceintures de roches vertes de la région, s'accordent avec les mécanismes de production de magma et de mise en place aux marges des plaques convergentes.[Traduit par l...

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“…1535±5 Ma , 16) Granite gris: 1498+4/-3 Ma , 17) Granite gneissique : 1485+63/-31 Ma , 18) Granite porphyrique : 1496+8/-7 Ma (Verpaelst et al, 1997a), 19) Porphyre felsique du lac Le Doré : 1510±10 Ma (Verpaelst et al, 1997a), 20) Porphyre felsique du lac Porphyre: 1503+6/-4 Ma (Verpaelst et al, 1997a), 21) Granite rapakivi : 1497+15/-9 Ma (Wodicka et al 2002), 22) Porphyre felsique de la rivière Olomane : 1495±2 Ma (Verpaelst et al, 1997a), 23) Granite tardif: 981±2 Ma , 24) Granite du Lac au 22 ème mille : l,3±0,l Ga (présente étude) 50 Wyoming (Stevenson et Patchett, 1990); b) de la partie centrale de la sousxin province de Uchi (Corfu et Stott, 1993;Corfu et Stott, 1996) -Edwards, 1972;Gower, 1996a). Ces roches ont été déformées et métamorphisées par l'orogenèse grenvillien à 1080-970 Ma (Gower, 1996b).…”

Section: Xllunclassified

“…Les rapports (Stevenson et Patchett, 1990); b) de la partie centrale de la sous-province de Uchi (Corfu et Stott, 1993 ;Corfu et Stott, 1996); c) des Gneiss d'Amîtsoq, ceux de la Formation Green Mountain et de la région de Gunnison au Colorado (Vervoort et Blichert-Toft, 1999); d) des échantillons du Groupe de Wakeham (cette étude). Les isotopes du plomb constituent un excellent outil pour l'étude de l'évolution de la croûte et du manteau car trois de ces isotopes radiogéniques sont issus de parents (U,Th) avec de longues demi-vies et deux d'entre eux sont des isotopes différents.…”

Section: Résultatsunclassified

Caractérisation géochimique (éléments majeurs et éléments en traces), traçage isotopique (Sm-Nd, Lu-Hf) et géochronologie (Pb-Pb, U-Pb) du groupe de Wakeham, N.E. Québec :

Youcef¹

2003

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Age and Petrogenesis of Two Late Archean Magmatic Suites, Northwestern Superior Province, Canada: Zircon U-Pb and Lu-Hf Isotopic Relations

Cited by 62 publications

References 0 publications

An Archean arc basalt–Nb-enriched basalt–adakite association: the 2.7 Ga Confederation assemblage of the Birch–Uchi greenstone belt, Superior Province

An Archean arc basalt–Nb-enriched basalt–adakite association: the 2.7 Ga Confederation assemblage of the Birch–Uchi greenstone belt, Superior Province

Age structure and orogenic significance of the Berens River composite batholiths, western Superior Province

Caractérisation géochimique (éléments majeurs et éléments en traces), traçage isotopique (Sm-Nd, Lu-Hf) et géochronologie (Pb-Pb, U-Pb) du groupe de Wakeham, N.E. Québec :

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