Diamonds in Canada

Kjarsgaard, B A; Levinson, A. A.

doi:10.5741/gems.38.3.208

“…В центре основания и непосредственно над килем находится впадина Гудзонова залива. В области архейской коры Северной Америки известны многочисленные проявления алмазоносных кимберлитов, промышленные месторождения алмазов размещены в провинции Слейв [Kjarsgaard, Levinson, 2002, и ссылки в этой работе]. Возраст «гарцбургитовых» алмазов в кимберлитовых трубках провинции Слейв, как и в Каапваальском и в Сибирском кратонах, заключен в интервале между 3.52 и 3.20 млрд лет [Gurney et al, 2010, и ссылки в этой работе].…”

Section: морфология литосферы северо-американского композитного кратонаunclassified

Images of a lower-crustal oceanic slab: Direct evidence for tectonic accretion in the Archean western Superior province

White¹,

Musacchio²,

Helmstaedt³

et al. 2003

Geol

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The structure of the Archaean crust of the North America has been studied based on the synthesis of geological and geophysical data, including seismic sections along LITHOPROBE Geotransects, magnetic and gravity anomaly maps, and seismic tomography data. The authors rely on the experience gained in the Russian Program of the deep geological and geophysical studies of the East European Craton. The juvenile Neoarchaean crust, containing the fragments of reworked Meso-and Paleoarchaean rocks, forms an asymmetric round-oval-shaped domain, wherein the geophysical, structural, and metamorphic parameters display a concentric zoning pattern. The Central zone occupies the Hudson Bay basin. The Internal zone (the northeastern and northern Superior Province) is mainly composed of the granulite facies of metaplutonic, metavolcanic and metasedimentary rocks. The External zone encompasses the southern Superior Province together with Hearne and Rae Provinces. This paper presents 3D crustal models of southern Superior Province. The crust development resulted from rifting and a partial disruption of the continental crust, short-term opening of the linear oceans, successive northward subduction and accretion of the ancient continental and juvenile Neoarchaean oceanic and island-arc terranes between ~2.78 and ~2.70 Ga. Subsequent events in the epicontinental environment, including formation of the metasedimentary belts, granulite facies metamorphism and intense ore formation processes, took place within the range from ~2.71 to ~2.63 Ga. The SCLM morphology within the limits of the Archaean North American Craton can be represented as a flattened overturned cone with a vertical axis (down to a depth of ~350 km). The Hudson Bay basin is located right above the lithospheric keel. A number of the main features of the structure and evolution of the Archaean crust of the North American Craton, primarily the ovalconcentric zoning, the important role of high-temperature magmatic and metamorphic processes and mainly intracontinental magmatism and sedimentation, indicates the leading role of the mantle-plume type processes. The Neoarchaean evolution of the North American craton represents the plate-tectonic processes initiated by a superplume. The Neoarchaean North American Craton is one of a series of similar phenomena that occurred ~2.75 Ga ago in a number of continental regions. The most important features, repeated to a certain degree in tectonic units of this type, are: (1) synchronous formation between 2.79 and 2.58 Ga; (2) mainly intracontinental development; (3) the prevalence of oval-shaped synformal tectonic structures of different ranks with some form of concentric zoning; (4) high-temperature magmatism (usually with the participation of enderbite-charnockites and gabbro-anorthosites) and metamorphism of the granulite facies; (5) a frequently repeated combination of high-grade (granulite and hightemperature amphibolites facies) and low-or moderate-grade (greenschist and epidote-amphibolite facies) metamorphic rocks; (6) the lower-c...

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“…В центре основания и непосредственно над килем находится впадина Гудзонова залива. В области архейской коры Северной Америки известны многочисленные проявления алмазоносных кимберлитов, промышленные месторождения алмазов размещены в провинции Слейв [Kjarsgaard, Levinson, 2002, и ссылки в этой работе]. Возраст «гарцбургитовых» алмазов в кимберлитовых трубках провинции Слейв, как и в Каапваальском и в Сибирском кратонах, заключен в интервале между 3.52 и 3.20 млрд лет [Gurney et al, 2010, и ссылки в этой работе].…”

Section: морфология литосферы северо-американского композитного кратонаunclassified

Deep Crustal Structure and Model of Neorchaean Evolution of the North American Craton

Mints¹,

Afonina²

2018

Geodin. tektonofiz.

0

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The structure of the Archaean crust of the North America has been studied based on the synthesis of geological and geophysical data, including seismic sections along LITHOPROBE Geotransects, magnetic and gravity anomaly maps, and seismic tomography data. The authors rely on the experience gained in the Russian Program of the deep geological and geophysical studies of the East European Craton. The juvenile Neoarchaean crust, containing the fragments of reworked Meso-and Paleoarchaean rocks, forms an asymmetric round-oval-shaped domain, wherein the geophysical, structural, and metamorphic parameters display a concentric zoning pattern. The Central zone occupies the Hudson Bay basin. The Internal zone (the northeastern and northern Superior Province) is mainly composed of the granulite facies of metaplutonic, metavolcanic and metasedimentary rocks. The External zone encompasses the southern Superior Province together with Hearne and Rae Provinces. This paper presents 3D crustal models of southern Superior Province. The crust development resulted from rifting and a partial disruption of the continental crust, short-term opening of the linear oceans, successive northward subduction and accretion of the ancient continental and juvenile Neoarchaean oceanic and island-arc terranes between ~2.78 and ~2.70 Ga. Subsequent events in the epicontinental environment, including formation of the metasedimentary belts, granulite facies metamorphism and intense ore formation processes, took place within the range from ~2.71 to ~2.63 Ga. The SCLM morphology within the limits of the Archaean North American Craton can be represented as a flattened overturned cone with a vertical axis (down to a depth of ~350 km). The Hudson Bay basin is located right above the lithospheric keel. A number of the main features of the structure and evolution of the Archaean crust of the North American Craton, primarily the ovalconcentric zoning, the important role of high-temperature magmatic and metamorphic processes and mainly intracontinental magmatism and sedimentation, indicates the leading role of the mantle-plume type processes. The Neoarchaean evolution of the North American craton represents the plate-tectonic processes initiated by a superplume. The Neoarchaean North American Craton is one of a series of similar phenomena that occurred ~2.75 Ga ago in a number of continental regions. The most important features, repeated to a certain degree in tectonic units of this type, are: (1) synchronous formation between 2.79 and 2.58 Ga; (2) mainly intracontinental development; (3) the prevalence of oval-shaped synformal tectonic structures of different ranks with some form of concentric zoning; (4) high-temperature magmatism (usually with the participation of enderbite-charnockites and gabbro-anorthosites) and metamorphism of the granulite facies; (5) a frequently repeated combination of high-grade (granulite and hightemperature amphibolites facies) and low-or moderate-grade (greenschist and epidote-amphibolite facies) metamorphic rocks; (6) the lower-c...

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“…Their association with glacial sediments in the Great Lakes region led Hobbs (1899) to propose that the diamonds had been transported by the southward movements of glaciers (which covered large portions of Canada during the Pleistocene epoch, from 2.5 million until about 12,000 years ago) from unknown source rocks in the area near Hudson Bay (see also Bell, 1906). Kjarsgaard and Levinson (2002) presented a comprehensive review of the discovery and development of Canada's diamond mines through the 1990s. Although the north-central areas of the country were known to be underlain by ancient rocks of Archean age-the rocks that also host diamondiferous kimberlites in southern Africa and elsewhere-there was little effort on the part of large mining companies to search for diamonds in the Slave craton (Pell, 1995;Carlson et al, 1999).…”

Section: Diamond Exploration In Canadamentioning

confidence: 99%

Mining Diamonds in the Canadian Arctic: The Diavik Mine

Shigley¹,

Shor²,

Padua³

et al. 2016

G&G

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The Diavik mine, located in the Archean-age Slave geologic province in northern Canada, is one of the world's preeminent sources of gem diamonds. Since mining operations began in 2003, it has produced over 100 million carats of diamonds. This article will review the discovery, development, and operation of the mine, which is situated in a remote subarctic setting in the Northwest Territories. Four kimberlite pipes occur in close proximity-three are being exploited, while the fourth will be brought into production in 2018. Diavik is now expected to operate through 2024; upon closure, the equipment, buildings, and infrastructure will be removed and the land returned as closely as possible to its original condition. Canada is the world's fourth-largest diamond producer, with most of that output coming from one area near Lac de Gras in the Northwest Territories. The discovery of kimberlite pipes there in the early 1990s led to the development of several major mines. Diamond-bearing kimberlite deposits that can be mined economically are noteworthy, since only about 50 such occurrences have been found worldwide since the

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Diamonds in Canada

Cited by 30 publications

References 20 publications

Images of a lower-crustal oceanic slab: Direct evidence for tectonic accretion in the Archean western Superior province

Images of a lower-crustal oceanic slab: Direct evidence for tectonic accretion in the Archean western Superior province

Deep Crustal Structure and Model of Neorchaean Evolution of the North American Craton

Mining Diamonds in the Canadian Arctic: The Diavik Mine

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