Rb-Sr and Nd-Sm isotopes in fluorite related to the granites of the Bushveld Complex

Kinnaird, Judith A.; Kruger, F. J.; Cawthorn, R. Grant

doi:10.2113/107.3.413

Cited by 25 publications

(17 citation statements)

References 38 publications

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“…Note that: (1) the Pb isotopic ratios of most of the tuyere and slag pieces are very variable but distinctly different from those of the tin prills; and (2) the isotopic ratios of the tin prills are highly variable but fall on a straight line (i.e., an isochron). The calculated 207 Pb/ 206 Pb age of the tin prill isochron is 2052 ± 34 Ma e a good match to the currently accepted radiometric age (2057 ± 3 Ma; Kinnaird et al, 2004) of the Lebowa Granite Suite, the source of the ore-forming fluids for the Rooiberg tin deposits. We therefore conclude that the tin prills did not pick up significant amounts of lead from either tuyeres or slags during smelting and that the line is a valid "fingerprint" for the Rooiberg tin deposits, to which tin samples of unknown provenance may be compared.…”

Section: Smelted Tinsupporting

confidence: 78%

“…The source of the fluids that formed the Rooiberg tin deposits were the granites of the Lebowa Granite Suite (LGS) of the BMP, which surround, and are presumed to underlie, the Rooiberg Fragment. LGS granites are dated to 2057 ± 3 Ma by multiple SHRIMP (Selective High Resolution Ion MicroProbe) analyses of single zircons (Kinnaird et al, 2004). Other tin deposits in Fig.…”

Section: Tin Ingots and Bronzes From Southern Africamentioning

confidence: 99%

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A novel approach to lead isotope provenance studies of tin and bronze: applications to South African, Botswanan and Romanian artifacts

Molofsky

Killick

Ducea

et al. 2014

Journal of Archaeological Science

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Section: Smelted Tinsupporting

confidence: 78%

Section: Tin Ingots and Bronzes From Southern Africamentioning

confidence: 99%

A novel approach to lead isotope provenance studies of tin and bronze: applications to South African, Botswanan and Romanian artifacts

Molofsky

Killick

Ducea

et al. 2014

Journal of Archaeological Science

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“…Type 1 cassiterite-tourmaline-sulphide mineralisation is considered to be syn-magmatic (fluid inclusion temperatures > 600°C; Pollard et al, 1991) and may either be endo-or exo-granitic. A syn-magmatic origin for this mineralisation is consistent with an unpublished SHRIMP weighted mean 207 Pb/ 206 Pb cassiterite age of 2049 ± 5 Ma (R. A. Armstrong, as referenced in Kinnaird et al, 2004). However, McNaughton et al (1993) obtained Pb-Pb whole rock isochron ages of between ca.…”

Section: Regional Geologysupporting

confidence: 84%

“…The LA-ICP-MS 207 Pb/ 206 Pb monazite age agrees well with the unpublished SHRIMP 207 Pb/ 206 Pb age of 2049 ± 5 Ma for assumed syn-magmatic Type-1 cassiterite mineralization, as quoted in Kinnaird et al (2004), whereas the SHRIMP 207 Pb/ 206 Pb is just slightly too old. The SHRIMP concordia age for the monazite is, however, consistent with the cassiterite age.…”

supporting

confidence: 85%

“…They comprise a differentiated sequence of sheet-like bodies with a total thickness of ~3 km (Kleemann and Twist, 1989). The Lebowa Granite Suite shows the widespread development of polymetallic synto post-magmatic mineralisation (Robb et al, 2000;Crocker et al, 2001;Baillie and Robb, 2004;Kinnaird et al, 2004) that can be divided into 4 types: 1. a cassiterite-tourmaline-sulphide association; 2. a molybdenite-fluorite-REE-sulphide association; 3. sulphide-carbonate ore bodies; and 4. a late stage fluorite-pitchblende-hematite association (Baillie and Robb, 2004).…”

Section: Introductionmentioning

confidence: 99%

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A La-Icp-MS and Shrimp U/Pb Age Constraint on the Timing of Ree Mineralisation Associated With Bushveld Granites

Buick

Lana

Gregory

2011

South African Journal of Geology

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Monazite occurs in association with fluorite and polymetallic sulphides in brecciated pegmatites emplaced within discordant pipelike structures, and spatially associated mineralised quartz veins that cut hydrothermally altered Bushveld-age Nebo Granite (Lebowa Granite Suite) on the farm Houtenbek 194 JR. Mineralisation of this style has been viewed as having a high-temperature origin related to a late-stage of Bushveld-age granite emplacement. However, early attempts to date Houtenbek monazite in the 1950 to 1960s, using thermal ionisation mass spectrometry, gave a range of very imprecise 207 Pb/ 206 Pb ages from isotopically moderately to strongly discordant grains that cannot be used to confidently make this link. Here we present new high spatial resolution SHRIMP and LA-ICP-MS weighted mean 207 Pb/ 206 Pb ages of 2059.2 ± 3.5 Ma and 2046 ± 10 Ma for a museum specimen of Houtenbek monazite. These estimates overlap with the 2054 Ma emplacement age of the main phase of the Lebowa Granite Suite. Together with the monazite REE patterns, which indicate a magmatic origin, the new age determinations reinforce the connection between REE mineralisation and Bushveld-age granites.

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Geochemical evolution of the Lebowa Granite Pluton in western Bushveld Igneous Complex, South Africa: More insight into the evolution of bimodal A‐type granitoid

Mutele

Misra

2021

Geological Journal

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The 2.05 Ga Bushveld Igneous Complex (BIC) in the Kaapvaal Craton, South Africa, with an areal extent of 65,000 km 2 , represents one of the largest bimodal A-type granitoid suites in the world. The igneous activity of this complex begun with the Rooiberg Group of basalt-rhyolite bimodal volcanism, followed by the emplacement of the ultramafic-mafic Rustenburg Layered Suite (RLS), and finally the granitoid rocks of the Rashoop Granophyre (RG) and Lebowa Granite Suite (LGS). In this study, we present our new borehole description and whole-rock chemical data on the LGS from the relatively unknown western BIC to constrain the origin of the LGS and try to evaluate their geochemical relationship to the Rooiberg Group felsic volcanics. In the western BIC, the LGS is locally represented by the hydrothermally altered Paalkraal Granite and the Kenkelbos Granite that together form a central dome-like feature. The Veekraal Granite forms the peripheral part of the dome. These granitoids are, in general, coarse-grained, porphyritic, or equigranular, showing granophyric intergrowth, and consist of quartz, perthitic microcline, and albitic plagioclase with minor opaque and interstitial hornblende/biotite. Our whole-rock chemical data on western LGS, along with those from the Groblersdal area, eastern BIC (taken as reference), form a cluster in the 'granite' field in the normative Ab-An-Or diagram with mean Or/(Ab+Or) 0.5 (0.11), and are peralkaline to weakly peraluminous in composition. These A-type granitoids are strictly 'ferroan' and calc-alkalic to alkali-calcic in nature, and evolved through partial melting as evident mainly in process identification plots. In bulk chemical composition, the LGS and high-SiO 2 Rooiberg Group rhyolites overlap with the experimental melts generated during dehydration melting of tonalite-granodiorite, indicating the Archaean Kaapvaal TTG as their possible source.Constraints from experimental petrology further suggest the pressure and temperature of this relatively anhydrous (≤1 wt% H 2 O) melting were 2-1 kbar (i.e., ≤7.5 km crustal depth) and 920 C, respectively. As suggested before, the parent magma of the voluminous mafic-ultramafic body (RLS) of the BIC, forming a voluminous magma chamber in shallow crustal depth, provided the heat for this partial melting event.The following igneous event as evident from field description in the literature, our new borehole description and whole-rock chemical data, were a limited chemical

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Rb-Sr and Nd-Sm isotopes in fluorite related to the granites of the Bushveld Complex

Cited by 25 publications

References 38 publications

A novel approach to lead isotope provenance studies of tin and bronze: applications to South African, Botswanan and Romanian artifacts

A novel approach to lead isotope provenance studies of tin and bronze: applications to South African, Botswanan and Romanian artifacts

A La-Icp-MS and Shrimp U/Pb Age Constraint on the Timing of Ree Mineralisation Associated With Bushveld Granites

Geochemical evolution of the Lebowa Granite Pluton in western Bushveld Igneous Complex, South Africa: More insight into the evolution of bimodal A‐type granitoid

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