Overview of Diamond Resources in Africa

Bhebe, Zi; Davidson, J. M.; Haggerty, Stephen E.; Hundt, Paul; Jacob, Jürgen; Lynn, Mike; Marshall, T.R.; Skinner, Charles; Smithson, Karl; Stiefenhofer, Johann; Robert, M.; Revitt, Anthony; Spaggiari, Renato; Ward, John D.; Wit, Maarten de

doi:10.18814/epiiugs/2016/v39i2/95776

Cited by 37 publications

(15 citation statements)

References 44 publications

(60 reference statements)

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“…The US$B13B cut-off for Tier 1 mines is approximately one-third lower than that suggested by De Beers (2014) and de Wit et al (2016), who placed the cut-off for Tier 1 diamond mines at US$20B. Our division at US$13B was selected based on a clear-cut break on a cumulative probability plot (Fig.…”

Section: Brief Historical Overview Of the Key Diamond Discoveriesmentioning

confidence: 92%

A Review of the Geology of Global Diamond Mines and Deposits

Kjarsgaard

Wit

Heaman

et al. 2022

Reviews in Mineralogy and Geochemistry

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Kjarsgaard et al.A Review of the Geology of Global Diamond Mines and Deposits 3 Table 1. Mineralogy of kimberlite, carbonate-rich olivine lamproite (CROL), and olivine lamproite. Minerals present Kimberlite Carbonate-rich olivine lamproite (CROL) Olivine lamproite Megacryst suite (> 1 cm) Common to absent Absent, rare Absent, ?very rare? Cognate and antecryst minerals Olivine Common to absent Rare to absent Rare to absent Phlogopite Minor to absent Common to minor Common, minor, rare Spinel Common to rare (spinel cores) Minor to absent (spinel cores) Minor to absent (spinel cores) Diopside Absent Rare to absent Rare to absent (Minor) Phenocryst /Microphenocrysts (0.2-1.0 mm) Olivine phenocrysts Common Common Common Olivine microphenocrysts Common Minor to rare Minor to rare Phlogopite phenocrysts Minor, rare, absent Common Common Phlogopite microphenocrysts Minor, rare (poikilitic) Common Common (poikilitic) Spinel phenocrysts Common to minor Minor to rare Minor to rare Diopside microphenocrysts Absent Variable: Common to absent Minor to absent Groundmass (<0.2 mm) Olivine Common Minor to rare Rare, absent Phlogopite Common, laths (poikilitic) Common (poikilitic) Common (poikilitic) Spinel Common to minor Minor to rare Minor to rare Glass Absent, exceptionally rare? Absent (not reported) Common, minor, rare Apatite Common to rare Common to minor Minor to rare Perovskite Common to minor, rare Minor to rare Minor to rare Carbonate (calcite, dolomite) Common to minor Common to minor Rare, absent

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Section: Brief Historical Overview Of the Key Diamond Discoveriesmentioning

confidence: 92%

A Review of the Geology of Global Diamond Mines and Deposits

Kjarsgaard

Wit

Heaman

et al. 2022

Reviews in Mineralogy and Geochemistry

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“…The Kimberley cluster includes five major kimberlite pipes (Kimberley, known as the “Big Hole,” De Beers, Wesselton, Bultfontein, and Du Toitspan), numerous smaller pipes, as well as an extensive system of dykes and sills (Figure 1). [ 23–29 ] About 30 kimberlite localities are known within a 10‐km radius around Kimberley. [ 30 ] Different dating techniques have constrained the emplacement ages of the Kimberley kimberlites between 81 and 92 Ma.…”

Section: Geological Setting and Sample Sitementioning

confidence: 99%

“…[ 31–38 ] The host lithologies include gneisses and less common shists and amphibolites of Archean crystalline basement, andesitic to basaltic lavas and meta‐sediments (quartzites) of Allanridge Group of the Ventersdorp Supergroup (~2.6–2.7 Ga), and flat‐lying sediments (shales and tillites) of the Dwyka Group of the Karoo Supergroup (Permo‐Carboniferous) that intruded by ~180–185 Ma of Karoo dolerite sills. [ 23–28,39,40 ]…”

Section: Geological Setting and Sample Sitementioning

confidence: 99%

Confocal Raman spectroscopic study of melt inclusions in olivine of mantle xenoliths from the Bultfontein kimberlite pipe (Kimberley cluster, South Africa): Evidence for alkali‐rich carbonate melt in the mantle beneath Kaapvaal Craton

Sharygin

Golovin

Tarasov

et al. 2021

J Raman Spectroscopy

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Identifying the composition of primary/primitive mantle melts is crucial for understanding the mantle's evolution and mantle‐derived magmatism. Melt inclusions in mantle xenoliths provide key information about such melts. This study used confocal Raman spectroscopy to characterize mineral assemblage of unexposed crystallized secondary melt inclusions in the olivine from the xenoliths of the sheared garnet peridotites from the Bultfontein kimberlite pipe (Kimberley cluster, Kaapvaal Craton, South Africa). The studied peridotites originated from 112‐ to 146‐km mantle depths. In total, 16 minerals were identified among daughter crysatls, which include carbonates (calcite, magnesite, dolomite), alkali carbonates (eitelite, nyerereite, gregoryite/natrite, K–Na–Ca–carbonate (K,Na)2Ca(CO3)2 (K analogue of nyerereite), alkali carbonates with additional anions (northupite, bradleyite, burkeite), alkali sulfates (glauberite, thenardite, aphthitalite), apatite, tetraferriphlogopite, and magnetite. Several more daughter minerals gave distinct Raman spectra, but they were not determined due to the lack of similar spectra in the databases. Carbonates are predominant among the daughter minerals in the melt inclusions. Many daughter minerals are rich in alkalis. These facts indicate that melt(s), parental for the inclusions, is alkali‐rich carbonate in composition. Two possible models were suggested for the origin of these melt inclusions: (1) in situ fracturing of olivine and the mantle melt infiltration shortly before the sheared peridotites were entrained by the ascending kimberlitic magma; (2) infiltration of the transporting kimberlite melt into xenoliths during ascent. Both models imply that the alkali‐rich carbonate melt(s) that interacted with peridotites originated at a greater depth than the entrapment level of studied xenoliths (>150 km), that is, at the base of the lithosphere or in the asthenosphere. This melt is genetically related to the kimberlite magmatism that formed the Bultfontein pipe and points at the alkali‐rich carbonate composition of primary kimberlite melt.

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“…Temporal distributions of global kimberlite occurrences have shown that kimberlites with Paleoproterozoic emplacement ages are extremely sparse. A few kimberlite occurrences with Early Precambrian ages are found in Central and South Africa and Eastern Australia [1,2]. The Kimozero metakimberlite is a unique Paleoproterozoic 1.92 Ga age kimberlite occurrence in the Karelian Craton [3][4][5][6].…”

mentioning

confidence: 99%

“…The Kimozero metakimberlite is a unique Paleoproterozoic 1.92 Ga age kimberlite occurrence in the Karelian Craton [3][4][5][6]. Nearly all Precambrian kimberlites can be found as macrocristic hypabyssal varieties, which occur as dykes or rarely as small bodies that represent a root part of the kimberlite pipes [1,2]. High erosion and alteration of ancient kimberlites have significantly complicated their volcanological reconstructions and have led to conclusions about the 'unusual' features of their explosive emplacement style and kimberlite composition [5,7], which differentiate them from Phanerozoic kimberlites.…”

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confidence: 99%

Paleoproterozoic Kimberlites of Kimozero: Petrographic Facies Reconstruction of Kimberlite Pipe Overcoming Tectonic and Metamorphic Modification

et al. 2020

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Based on a detailed petrographic investigation and geological observations of the Paleoproterozoic Kimozero kimberlite (Karelia, Russia), we present a new model of kimberlite pipe with multiphase and mono-crater structure. We recognised volcanoclastic and coherent kimberlite series that filled the inner and outer zones of the kimberlite crater. The multiphase structure, emplacement style, petrography and reconstructed size of the Kimozero kimberlite correspond to Phanerozoic kimberlite pipes.

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Overview of Diamond Resources in Africa

Cited by 37 publications

References 44 publications

A Review of the Geology of Global Diamond Mines and Deposits

A Review of the Geology of Global Diamond Mines and Deposits

Confocal Raman spectroscopic study of melt inclusions in olivine of mantle xenoliths from the Bultfontein kimberlite pipe (Kimberley cluster, South Africa): Evidence for alkali‐rich carbonate melt in the mantle beneath Kaapvaal Craton

Paleoproterozoic Kimberlites of Kimozero: Petrographic Facies Reconstruction of Kimberlite Pipe Overcoming Tectonic and Metamorphic Modification

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