UNIVERSITE DU QUEBEC MEMOIRE PRÉSENTÉ À …

2013-7-12 · notamment le cas du complexe du Bushveld en Afrique du Sud qui est au cœur des travaux présentés ici. Le complexe du Bushveld, formé il y a 3,5 milliards d''années, est une intrusion magmatique de taille exceptionnelle (200 km x 300 km). Tout comme les métaux de base et les ÉGP, le sélénium s''associe aux sulfures.

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Le complexe du Bushveld

2007-1-29 · Le Complexe du Bushveld affleure de façon discontinue, dans les lobes évoqués plus haut. Il semble néanmoins probable qu''il s''agisse d''une intrusion continue en profondeur, c''est à dire que les lobes ne soient que la partie affleurante d''un complexe encore plus grand, formant un sill, plat et arrondi (9 km d''épaisseur sur 300 ...

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Compressive deformation in the floor rocks to the …

Localement, elles peuvent avoir été assimilées par le Complexe du Bushveld. Après la mise en place du Complexe du Bushveld, il y a eu peu de mouvements le long de la Faille, surtout là où la Faille passe sous les régions occupées par le Complexe du Bushveld. ... Du Plessis and Walraven (1990); Uken and Watkeys (1997a, 1997b), Cawthorn ...

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Crystallization Sequence and Magma Chamber Processes …

Large layered intrusions, such as the Bushveld complex, South Africa (Cawthorn et al., 1991; Mitchell et al., 1998; Kruger, 2005) or the Bjerkreim–Sokndal intrusion, Norway (Nielsen et al., 1996; Wilson et al., 1996), are often characterized by frequent magma chamber replenishments during crystallization, whereas smaller magma bodies such as ...

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Large igneous provinces (LIPs) and carbonatites | …

2009-10-1 · There is increasing evidence that many carbonatites are linked both spatially and temporally with large igneous provinces (LIPs), i.e. high volume, short duration, intraplate-type, magmatic events consisting mainly of flood basalts and their plumbing systems (of dykes, sills and layered intrusions). Examples of LIP-carbonatite associations include: i. the 66 Ma Deccan …

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Postemplacement dynamics of basaltic intrusions in the ...

2017-2-6 · Igneous layers can be traced across them in many cases but can be discontinuous in some. The Bushveld Complex, South Africa, for example, has thick peripheral lobes displaying a well‐defined basal igneous sequence that is missing from the thinner central area [Cawthorn and Webb, 2001; Webb et al., 2004; Cole et al., 2014].

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The formation of vanadium deposits in the Archean …

2018-1-3 · (e.g. Upper Zone of the Bushveld Complex, South Africa; Reynolds, 1985b), or those in which a magma chamber behaves as an open system, and Fe-Ti-V oxide ore horizons form through multiple injections of magma (e.g. Panzhihua intrusion, …

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RELATIONSHIP BETWEEN PGE AND PGM IN THE …

R. Grant Cawthorn § 1. Department of Geology, University of the Witwatersrand, PO Wits, 2050, South Africa ... dans les secteurs ouest et est du complexe de Bushveld, en Afrique du Sud. Les teneurs des sections exploitées de ce banc sont uniformes, entre 5 et 7 g/t, sur une distance de 100 km, sauf à la mine Union, où la teneur est ...

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Documents dans le département, le module, le service ou l ...

Rôle des liquides sulfurés dans la formation des minéralisations riches en éléments du groupe du platine : applications au complexe du Bushveld (Afrique du Sud) et au Complexe de Stillwater (États-Unis). Thèse de doctorat, Université du Québec à Chicoutimi. Goghrod Hamid. (1993).

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Somali Plate

Distribution of platinum-group elements in the Platreef at Overysel, northern Bushveld Complex: a combined PGM and LA-ICP-MS study. Contributions to Mineralogy and Petrology, 154(2), 171-190. Actinolite Buranga pegmatite, Muhororo, Ngororero District, Western Province, Rwanda

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Mantle-derived magmas and magmatic Ni-Cu-(PGE) …

2021-10-25 · Bushveld Complex in South Africa and the Stillwater Complexe in the USA have been interpreted as crustally contaminated komatiite (Irvine, 1977; Barnes, 1989; Maier et al., 2000), boninite (Hatton and Sharpe, 1988), or a partial melt of metasomatised sub-continental

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VARIATIONS IN THE NATURE OF THE PLATINUM …

2011-12-15 · The Bushveld Complex is a major source of the world''s platinum-group element (PGE) supplies, the majority of which are hosted in the Merensky Reef and underlying UG2 chromitite (Vermaak 1976, Cawthorn et al. 2002a). The Merensky Reef is a mining term used to refer to the zone where the exploitable PGE grades

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The Loskop Formation and its relationship to the Bushveld ...

The Loskop Formation consists of continental detrital red beds (sensu lato), 2.06 Ga old, laid down in the Cullinan-Witbank Basin.These beds rest conformably to unconformably on the Rooiberg volcanics and on the Pretoria Group, and have been partly eroded before the deposition of the Waterberg Group.

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Revue canadienne de géographie tropicale | Three ...

Figure 1: Geological map of the Bushveld Complex with the Rustenburg Layered Suite (RLS) and the Bushveld granites by Cawthorn et al., 2006. The geometry of the Bushveld Igneous Complex BIC was first described as a lopolith by Hall (1932).

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Subsurface geometry of the northwestern Bushveld …

Abstract: The surbsurface geometry of the Rustenburg Layered Suite (RLS) in the northwestern part of the Bushveld Complex was investigated by analysis two hundred borehole log data.The objective of this study is to produce a regional-scale 3D model. A geostatistical method was employed in analysing the borehole logs lithostratigraphic units.

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Canadian Journal of Tropical Geography | Three …

Figure 1: Geological map of the Bushveld Complex with the Rustenburg Layered Suite (RLS) and the Bushveld granites by Cawthorn et al., 2006. The geometry of the Bushveld Igneous Complex BIC was first described as a lopolith by Hall (1932).

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Origin of Anorthosite and Magnetitite Layers in the ...

In the case of the Bushveld Complex, the proportion of trapped liquid in Main and Upper Zone rocks is typically about 10% (Cawthorn & McCarthy, 1985). This component would contribute about 6% more plagioclase and 4% of mainly pyroxene (and oxide in the Upper Zone).

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Platinum-Group Element Deposits in Layered Intrusions ...

2015-5-19 · Cawthorn RG (2002) Platinum-group element deposits in the Bushveld Complex, South Africa. In: Cabri LJ (ed) Geology, Geochemistry, Mineralogy and Mineral benefication of Platinum Group Element, vol Special Volume 54. Canadian Institute of Mining, Metallurgy and Petroleum, pp 389–429 Google Scholar

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Mineral layering in the Bushveld Complex; implications of ...

The Cr abundances in magnetite separates from the Main Magnetite layer, 1 magnetite layers 1 and 2, and the intervening anorthositic horizons have been determined from two widely spaced localities in the eastern Bushveld Complex. Chromium abundance is greatest at the base of the Main Magnetite layer (around 7,000 ppm) and decreases rapidly with height through this layer …

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Igneous Rock Associations 23. The Bushveld Complex, …

The Bushveld has been the sub-ject of geological study since 1872, evidently having engen-dered on the order of 200 publications by the 1930s (Eales 2014), on the order of a thousand by the 1970s (see Cawthorn 2015; p. 521), and thousands since then (nearly 3000 publica-tions since 1994 contain ''Bushveld Complex'' in their titles,

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Experimental effects of pressure and fluorine on apatite ...

2008-2-6 · Tegner C, Cawthorn RG, Kruger FJ (2006) Cyclicity in the Main and Upper Zones of the Bushveld Complex, South Africa: crystallization from a Zoned Magma Sheet. J Petrol:1–23. Tollari N, Toplis MJ, Barnes S-J (2006) Predicting phosphate saturation in silicate magmas: an experimental study of the effects of melt composition and temperature.

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Ore-forming processes in the upper part of the Bushveld ...

Ore Geology Reviews, Volume 65, Part 4, 2015, pp. 917-928. Show abstract. The Sokoman Iron Formation in the Labrador Trough, Canada, a typical granular iron formation (GIF), is coeval with the ~ 1.88 Ga Nimish volcanic suites in the same region. It is composed of the Lower, Middle and Upper Iron Formations.

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mémoire allami

Petrologic evolution of partially molten cumulate: the Atok section of the Bushveld complex. contributions to Mineralogy and Petrology,129, pp.20-34. McDonough et Sun S. (1995).The Composition of the Earth, Chemical Geology volume 120, pp.223-253 Medard E. (2005).

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Minerals | Free Full-Text | An Integrated Model for ...

The titanomagnetite of the Lac Doré Complex, an Archean layered intrusion that is located in the Abitibi greenstone belt in Québec (Canada), contains a wide variety of exsolution textures, which are the remnants of a complex cooling history. In the present study, we reconstitute the decomposition stages of the original solid solution in order to explain the formation of ilmenite, …

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The chromite deposits of the Troodos complex, cyprus ...

The Troodos ophiolite of Cyprus hosts chromite deposits both as podiform bodies within the basal harzburgite and as lesser layers and schlieren within the overlying dunites and clinopyroxene dunites of the metacumulate sequence. All chromitite types have been studied from both field and mineralogical aspects, with particular emphasis on the chemistry of the ubiquitous silicate …

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Effets de la contamination continentale et des ...

2021-10-24 · Complexe du Bushveld Fig. 1.1 – Localisation géographique du complexe igné du Bushveld. 1.1.1 Le craton du Kaapvaal La carte du craton tel qu''il se présente actuellement est proposée en Fig. 1.2. Une reconstitution de l''histoire du craton du Kaapvaal est synthétisée par McCourt (1995). À la suite d''un amalgame de terrains, les ...

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Disequilibrium Dihedral Angles in Layered Intrusions: a ...

Photomicrographs of microstructures in mafic rocks. All images are dominated by augite (high relief) and plagioclase (clear). (a) Sample ROM48-32 from the ∼3 m thick Traigh Bhàn na Sgùrra sill (Holness & Humphreys, 2003; Holness et al., 2012b) (plane-polarized light).The augite infills the spaces between the plagioclase laths, with almost perfect pseudomorphing of the original …

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