Chapter 12 The Circum-Superior Belt: A Proterozoic Plate Margin?

Baragar, W R A; Scoates, R F J

doi:10.1016/s0166-2635(08)70017-3

Cited by 37 publications

(19 citation statements)

References 36 publications

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“…A key region is the Trans-Hudson Orogen in Canada where a variety of 1.9-1.8 Ga rocks accreted onto two separate Archean cratons. The Circum-Superior belt wraps around Superior Craton, from Labrador in the east to Saskatchewan in the west where it disappears under younger cover (Baragar and Scoates, 1981). The northern and eastern parts of the belt, which consists primarily of volcanic and sedimentary rocks, formed as a passive margin; in the west, a series of island arcs and exotic terranes accreted against the older craton.…”

Section: ) As Well As In the Gawlermentioning

confidence: 99%

Formation and Evolution of the Continental Crust

Arndt¹

2013

GeochemPersp

233

117

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Section: ) As Well As In the Gawlermentioning

confidence: 99%

Formation and Evolution of the Continental Crust

Arndt¹

2013

GeochemPersp

233

117

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“…Early models proposed that the Cape Smith foldhelt represented a major suture resulting from the collision of two continents (Gibb and Walcott, 1971). Others interpreted the foldbelt as an in-situ rifted segment of the CircumSuperior foldhelt (Baragar and Scoates, 1981). Likewise, Francis et aL (1983), Hynes andFrancis (1982) and Picard et al (1990) proposed that the Povungnituk and the Chukotat Groups were the result of progressive opening of an oceanic rift.…”

Section: • •mentioning

confidence: 99%

Enriched mantle components in Proterozoic continental-flood basalts of the Cape Smith foldbelt, northern Québec

Modeland¹,

Francis²,

Hynes³

2003

Lithos

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“…Literature data on the tectonic environments of geologic complexes (Peive et al 1972, Piirainen et al 1974, Hain 1977, Archibald et al 1978, Condie 1980, Baragar and Scoates 1981, Barton and Key 1981, Jackson and Iannelli 1981, Gaal 1982, Sims et al 1982, Milanovskii 1983 and their comparison with the ones in nickeliferous epiarchean provinces, for which the geotectonic conditions can be determined with more confidence, confirm the above. The initial point of the paleotectonic analysis, the results of which are in Table 2, is the Sawkins' model (Sawkins 1972).…”

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confidence: 57%

Peridotitic Komatiites and the Origin of Ores (Southeastern Part of the Baltic Shield)

Kochnev-Pervukhov

Zaskind

Proskuryakov³

1986

Special Publication No. 4 of the Society for Geology Applied to Mineral Deposits

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Komatiite magmatism of the Archean greenstone belts of the southeastern part of the Baltic shield is considered here. The conformable bedding and interbedding of bodies of komatiites with pillow basalts and horizons of tuffs, with breccias at their tops, pillows, amygdules, glass and spinifex textures permit the determination of these rocks as peridotite komatiite lavas. Plutonic analogs of these rocks are found in ultramafic effusion feeders. Nickel-copper ore mineralization is orthomagmatic and is associated with komatiitic intrusives. The nickel ore potential of units associated with komatiite magmatism seems .to be correlated with the appearance of island-arc basalts: the larger these are, the smaller the ore potential of the structures. And, in this sense, the nearest analogs of the belts in the Baltic shield are the Canadian greenstone belts, not the Western Australian. These may be considered geotectonically as nickeliferous provinces.The southeastern part of the Baltic shield is a region of wide spreading greenstone belts; these are filled with Archean series and form a complicated network of the narrow elongated structures within gneissose granite blocks (Fig. 1). The extension of the belts ranges from 1 -2 km to a few tens of kilometers. In a number of such structures, komatiitic series are found (Fig. 1). The authors studied the volcanic-plutonic komatiite complex in the Kenozero-Kozhozero greenstone belt.Komatiitic bodies have ~arious lengths and thicknesses and conform with basalt sheets. Deformational and metamorphic changes in such basalts and komatiites are much the same. The generalized section of the researched bodies consists of two parts (Fig. 2): the upper, less thick part, is composed of breccias and vitreous and spinifex rocks; the lower part of serpentinite after ordinary peridotite and dunite. The ratio of thicknesses of the upper and lower parts fluctuates from 1: 10 to 1: 50.The glass, the skeletal forms of magmatic minerals, and the spinifex textures are doubtless evidences of the crystallization of these rocks from a melt under high temperature-gradient conditions. The composition of the melt is determined from the composition of altered glass and rocks with spinifex textures (Table 1), and corresponds to that of peridotite komatiites (Arndt et al. 1979, Brooks and

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Chapter 12 The Circum-Superior Belt: A Proterozoic Plate Margin?

Cited by 37 publications

References 36 publications

Formation and Evolution of the Continental Crust

Formation and Evolution of the Continental Crust

Enriched mantle components in Proterozoic continental-flood basalts of the Cape Smith foldbelt, northern Québec

Peridotitic Komatiites and the Origin of Ores (Southeastern Part of the Baltic Shield)

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