A domain-based digital summary of the evolution of the Palaeoproterozoic of North America and Greenland and associated unconformity-related uranium mineralization

Eglington, B. M.; Pehrsson, S J; Ansdell, Kevin M.; Lescuyer, Jean-Luc; Quirt, David; Milési, Jean Pierre; Brown, P. R.

doi:10.1016/j.precamres.2013.01.021

Cited by 47 publications

(15 citation statements)

References 79 publications

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“…(Williams et al 1991). With the disappearance of the District of Keewatin as a political entity, Hank's cratons reverted to their synonyms, the Rae and Hearne cratons respectively (Hoffman 1988;Eglington et al 2013). The collision zone between the two cratons, originally inferred from reconnaissance geology, gravity gradient maps, aeromagnetic discontinuities, and seismic soundings (Taylor 1963;Sharpton et al 1987;Hoffman 1990;Ross et al 1995), has been confirmed in the last decade by inter-cratonic comparative geology, igneous petrology, metamorphic thermobarometry, and U-Pb geochronology (Mahan et al 2006;Berman et al 2007;Martel et al 2008).…”

Section: Sommairementioning

confidence: 94%

“…This segment of the orogen includes three episodes of collision (Wardle et al 2002;van Gool et al 2002;St-Onge et al 2006Berman et al 2013;Corrigan et al 2009;Corrigan 2013;Eglington et al 2013;Pehrsson et al 2013a;Partin et al 2014). The first, 1.88-1.86 Ga, involved the accretion of Archean microcontinents (Sugluk, Meta Incognita, Southeast Churchill Core Zone, Disco and North Atlantic) to the Rae craton.…”

Section: Trans-hudson Orogenmentioning

confidence: 99%

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The Origin of Laurentia: Rae Craton as the Backstop for Proto-Laurentian Amalgamation by Slab Suction

Hoffman

2014

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Proto-Laurentia (i.e. pre-Grenvillian Laurentia) is an aggregate of six or more formerly independent Archean cratons that amalgamated convulsively in geons 19 and 18 (Orosirian Period), along with non-uniformly distributed areas of juvenile Paleoproterozoic crust. Subduction polarities and collision ages have been provisionally inferred between the major cratons (and some minor ones), most recently between the Rae and Hearne cratons. The oldest Orosirian collisions bound the Rae craton: 1.97 Ga (Taltson-Thelon orogen) in the west, and 1.92 Ga (Snowbird orogen) in the southeast. All other Orosirian collision ages in proto-Laurentia are < 1.88 Ga. The Rae craton was the upper plate during (asynchronous) plate convergence at its western and, tentatively, southeastern margins. Subsequent plate convergence in the Wopmay and Trans-Hudson orogens was complex, with the Rae craton embedded in the lower plate prior to the first accretion events (Calderian, Reindeer and Foxe orogenies), but in the upper plate during major subsequent convergence and terminal collisions, giving rise to the Great Bear and Cumberland magmatic arcs, respectively. The ‘orthoversion’ theory of supercontinental succession postulates that supercontinents amalgamate over geoidal lows within a meridional girdle of mantle downwellings, orthogonal to the lingering superswell at the site of the former supercontinent. If the downwelling nodes develop through positive feedback from the descent of cold oceanic slabs, then viscous traction should contribute to drawing the cratons together over the downwelling node. Viewed in this way, the Rae craton was the first to settle over the downwelling node and became the backstop for the other cratons that were drawn towards it by subduction. It was, literally, the origin of Laurentia. Whether the Rae craton was also the origin of Nuna, the hypothetical cogenetic supercontinent, depends on ages and subduction polarities of Orosirian sutures beyond proto-Laurentia.SOMMAIRELa proto-Laurentie (c.-à-d. la Laurentie pré-grenvillienne) est un agrégat d’au moins six cratons archéens indépendants qui se sont amalgamés convulsivement durant les géons 19 et 18 (Orosirien), le long de zones de croûtes juvéniles paléoprotérozoïques réparties de manière hétérogène. Les polarités de subduction et les âges de collision entre les grands cratons (et d’autres moins grands) ont été provisoirement déduits, le plus récemment entre le craton de Rae et le craton de Hearne. Les plus anciennes collisions orosiriennes ont soudé le craton de Rae : 1,97 Ga (orogène de Taltson-Thelon) dans l’ouest, et 1,92 Ga (orogène de Snowbird) dans le sud-est. Tous les autres âges de collision en proto-Laurentie sont inférieurs à 1,88 Ga. Le craton de Rae constituait la plaque supérieure durant la convergence de plaque (asynchrone) à sa marge ouest, et peut-être aussi à ses marges sud-est. La convergence de plaque subséquente dans les orogènes de Wopmay et Trans-Hudson a été complexe, le craton de Rae étant encastré dans la plaque inférieure avant les premiers événements d’accrétion (orogènes caldérienne, de Reindeer et de Fox), puis dans la plaque supérieure durant la grande convergence subséquente et les collisions terminales, ce qui a créé les arcs magmatiques de Great Bear et de Cumberland respectivement. La théorie de « l’orthoversion » de la succession des supercontinents présuppose que les supercontinents s’amalgament au-dessus de creux géoïdaux en deça d’une gaine méridienne de convections mantéliques descendantes, à angle droit d’un super-renflement persistant au site d’un ancien supercontinent. Si le nœud de convection descendante s’établit par rétroaction positive de la descente de plaques océaniques froides, la traction visqueuse devrait contribuer à entraîner les cratons ensembles au-dessus du nœud de convection descendante. Vu de cette façon, le craton de Rae a été le premier à s’établir au-dessus du nœud de convection descendante, ce qui en a fait la butée des autres cratons entraînés par la subduction. Littéralement, telle a été l’origine de la Laurentie. Quant à savoir si c’est le craton de Rae qui a été à l’origine de Nuna, cet hypothétique surpercontinent cogénétique, cela dépend des âges et des polarités de subduction des sutures orosiriennes au-delà de la proto-Laurentie.

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Section: Sommairementioning

confidence: 94%

Section: Trans-hudson Orogenmentioning

confidence: 99%

The Origin of Laurentia: Rae Craton as the Backstop for Proto-Laurentian Amalgamation by Slab Suction

Hoffman

2014

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“…In tectonic reconstructions, the Paleoproterozoic western Churchill Province (WCP) is centrally placed within the large continent Laurentia (Hoffman, 1988), which became part of supercontinent Nuna (Eglington et al, 2013). The WCP is composed of two dominantly Archaean subprovinces, the Rae and Hearne, which collided at the beginning of the amalgamation of Laurentia near 1.9 Ga (Berman et al, 2007).…”

Section: Tectonic Setting and Regional Geologymentioning

confidence: 99%

“…1.83 Ga) and of Laurentia with a composite Congo-West Africa-Amazonia continent (ca. 1.80 Ga; Eglington et al, 2013). Both the Rae and Hearne provinces were intruded by anorogenic granites (commonly rapakivi-textured) at about 1.75 Ga.…”

Section: Tectonic Setting and Regional Geologymentioning

confidence: 99%

“…16. The Nuna supercontinent at 1750 myrs (after Eglington et al, 2013) with locations of prominent 1.73-1.77 Ga anorogenic granite provinces and mafic dyke swarms (see Table 4). Abbreviations of continental fragments/cratons: Am = Amazonia, Au = Australia, Ba = Baltica, Co = Congo, He = Hearne, In = India, Ka = Karelia, NA = North Atlantic, NC = North China, NS = North Siberia, Ra = Rae, Pa = Proto-Australia, Sc = South China, SI = Slave, SF = Sao Francisco, SS = South Siberia, Su = Superior, WA = West Africa, WAu = West Australia, Wy = Wyoming.…”

Section: Origin Of Nueltin Granitementioning

confidence: 99%

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The Kivalliq Igneous Suite: Anorogenic bimodal magmatism at 1.75Ga in the western Churchill Province, Canada

Peterson

Scott

LeCheminant

et al. 2015

Precambrian Research

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The 3‐dimensional construction of the Rae craton, central Canada

Snyder

Craven

Pilkington

et al. 2015

Geochem Geophys Geosyst

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Reconstruction of the 3‐dimensional tectonic assembly of early continents, first as Archean cratons and then Proterozoic shields, remains poorly understood. In this paper, all readily available geophysical and geochemical data are assembled in a 3‐D model with the most accurate bedrock geology in order to understand better the geometry of major structures within the Rae craton of central Canada. Analysis of geophysical observations of gravity and seismic wave speed variations revealed several lithospheric‐scale discontinuities in physical properties. Where these discontinuities project upward to correlate with mapped upper crustal geological structures, the discontinuities can be interpreted as shear zones. Radiometric dating of xenoliths provides estimates of rock types and ages at depth beneath sparse kimberlite occurrences. These ages can also be correlated to surface rocks. The 3.6–2.6 Ga Rae craton comprises at least three smaller continental terranes, which “cratonized” during a granitic bloom. Cratonization probably represents final differentiation of early crust into a relatively homogeneous, uniformly thin (35–42 km), tonalite‐trondhjemite‐granodiorite crust with pyroxenite layers near the Moho. The peak thermotectonic event at 1.86–1.7 Ga was associated with the Hudsonian orogeny that assembled several cratons and lesser continental blocks into the Canadian Shield using a number of southeast‐dipping megathrusts. This orogeny metasomatized, mineralized, and recrystallized mantle and lower crustal rocks, apparently making them more conductive by introducing or concentrating sulfides or graphite. Little evidence exists of thin slabs similar to modern oceanic lithosphere in this Precambrian construction history whereas underthrusting and wedging of continental lithosphere is inferred from multiple dipping discontinuities.

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A domain-based digital summary of the evolution of the Palaeoproterozoic of North America and Greenland and associated unconformity-related uranium mineralization

Cited by 47 publications

References 79 publications

The Origin of Laurentia: Rae Craton as the Backstop for Proto-Laurentian Amalgamation by Slab Suction

The Origin of Laurentia: Rae Craton as the Backstop for Proto-Laurentian Amalgamation by Slab Suction

The Kivalliq Igneous Suite: Anorogenic bimodal magmatism at 1.75Ga in the western Churchill Province, Canada

The 3‐dimensional construction of the Rae craton, central Canada

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