Sulphur saturation in the lower and critical zones of the Eastern Bushveld Complex

McCarthy, T. S.; Lee, C.A; Fesq, H.W.; Kable, E.J.D.; Erasmus, C.S.

doi:10.1016/0016-7037(84)90192-3

Cited by 16 publications

(4 citation statements)

References 29 publications

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“…Generally, the ultrabasic rocks have a low LREE concentration and the low LREE fractionation. However, the HREE concentration and the HREE fractionation in ultrabasic rock were higher [7]. It could be concluded that the Serting Granite, Lui Granite and Kemayan Granite were slightly basic in composition.…”

Section: Discussionmentioning

confidence: 86%

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Geochemical study of Palong Pluton at Negeri Sembilan-Pahang border

Din

Umor

2013

AIP Conference Proceedings

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Abstract. The geochemical studies are carried out for igneous rocks from Palong Pluton at the border area of Negeri Sembilan and Pahang. The study area is about 250 km 2 , covering the area of Kemayan, Pasoh and Serting. The purposes of the geochemical study are to classify and determine the chemical characteristic of the granitic rocks, to correlate and interpret the crystallization history of igneous rocks, to determine the rock genesis and and to determine the origin of magma. The Palong Pluton is divided into three groups,

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Section: Discussionmentioning

confidence: 86%

“…The process was similar when Granite Lui was differentiated to Granite Serting. This finding was in aggrement with the fact that partial melting would cause the LREE to be liberated earlier when the rock melt, and the concentration of LREE was rich in the melting materials [7].…”

Section: Discussionmentioning

confidence: 96%

Geochemical study of Palong Pluton at Negeri Sembilan-Pahang border

Din

Umor

2013

AIP Conference Proceedings

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“…1993). Sulphides occur not only in tiie well known ore deposits like the Merensky Reef, but throughout most of its stratigraphy (Liebenberg, 1970;Von Gruenewaldt, 1976;McCarthy et al, 1984). In most Bushveld rocks, Ni is the dominant minor component in pyrrhotite.…”

Section: Introductionmentioning

confidence: 96%

The systematics of Co, Ni, and Cu contents in pyrrhotite from the upper zone of the western Bushveld Complex, South Africa

Merkle

2008

South African Journal of Geology

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Systematic relationships between the concentrations of Co. Ni, and Cu and the metal/sulphur nitio in pyrrhotite from the upper zone of the Bushveld Complex, South Africa were investigated. Due to the long cooling history of the Bushvekl Complex, a very efficient exsolution of pentlandite and chalcopyrite from the pyrrhotite took place. Based on 3122 microprobe analyses of pyrrhotite coexisting with pentlandite over a stratigraphie interval of 676.5 m, and 1092 additional analyses from one sample it was possible to show that especially the concentrations of Co and Ni are very low compared to many values in the literature. A systematic decline in Co and Ni with increasing metal/.sulphur ratio in pyrrhotite was observed, while no systematic relationship for Cu could be established.

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“…While it has been convincingly demonstrated that the Platreef mineralization formed in response to assimilation of sulfidic dolomite by a Merensky reeflike magma (e.g., Buchanan et al, 1981;Gain and Mostert, 1982), the origins of the Merensky and UG-2 deposits, in particular the factors responsible for their exceptionally rich platinum-group element content and belated appearance in the crystallization history of the layered marie sequence, are the subject of much current speculation (e.g., Vermaak, 1976a;von Gruenewaldt, 1979;Campbell et al, 1983;Irvine et al, 1983;McCarthy et al, 1984). Of prime interest in this regard is whether these ores owe their origin to some unrecognized • •agma chamber processes, to characteristics inherited at the time of magma generation in the source region, or to a fortuitous combination of both the above.…”

Section: Introductionmentioning

confidence: 98%

Sulfur saturation and second-stage melts; application to the Bushveld platinum metal deposits

Hamlyn¹,

Keays²

1986

Economic Geology

152

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A model is presented for the formation of platinum-group element ores by precipitation from sulfur-deficient, platinum-group element-rich, second-stage magmas. Numerous investigations indicate that basaltic magmas originating from undepleted or mildly depleted source regions are sulfur saturated at the time of eruption. Mantle-derived peridotites residual from midocean ridge basalt magma genesis have Pd abundances that are uniformly too high for it to have originated solely from silicate melt retained in the source region at the time of segregation; they imply the presence of an accessory immiscible sulfide melt to host the platinumgroup elements. The very high sulfide melt-silicate melt partition coefficients of the platinumgroup elements would result in strong fractionation of these metals into the accessory sulfide component during the melting event. The extreme platinum-group element enrichment of this accessory sulfide component is evidenced by the discovery ofplatinoid minerals in residual mantle nodules containing Pd (and Pt) abundances at the low ppb level (Keays et al., 1981).Magmas generated by low to moderate degrees of partial melting of undepleted mantle are therefore sulfur saturated at the time of segregation. These (first-stage) magmas become impoverished in platinum-group elements during the early stages of fractional crystallization because of coprecipitation of an immiscible sulfide phase (e.g., midocean ridge basalt glasses average <0. ppb Pd). Further melting of this depleted source leads to complete dissolution of the residual platinum-group element-rich sulfide component and production of secondstage magmas enriched in them but poor in sulfur.Boninitic magmas, generally regarded as second-stage melts generated from strongly depleted mantle sources, have enhanced platinum-group element abundances (mean Pd = 15 ppb) in agreement with the above model. During fractionation of these S-deficient magmas the concentration of platinum-group elements will build up until the onset of sulfur saturation and segregation of sulfides. These sulfides will generally have a higher platinum-group element tenor than those segregating from first-stage melts.A marked similarity in the composition of boninitic magmas and early parental magmas proposed for the Bushveld Complex (Davies et al., 1980;Sharpe, 1981), and possibly other intrusions hosting platinum-group element ores, suggests that their source regions have evolved in a similar manner. This accounts for the timing of deposition of the UG-2 and Merensky cyclic units in the upper partition of the critical zone and the unusual platinum-group elementrich nature of their ores. If this model is relevant to the Bushveld platinum-group element mineralization, then it provides a means of assessing the potential of other stratiform intrusions to host economic platinum-group element deposits.

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Sulphur saturation in the lower and critical zones of the Eastern Bushveld Complex

Cited by 16 publications

References 29 publications

Geochemical study of Palong Pluton at Negeri Sembilan-Pahang border

Geochemical study of Palong Pluton at Negeri Sembilan-Pahang border

The systematics of Co, Ni, and Cu contents in pyrrhotite from the upper zone of the western Bushveld Complex, South Africa

Sulfur saturation and second-stage melts; application to the Bushveld platinum metal deposits

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