Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Premier Mine

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Occurrence number: 
151-00-022
Country: 
South Africa
Region: 
Pienaars River Alkaline Complex (Franspoort Line)
Location: 
Longitude: 28.43, Latitude: -25.42
Carbonatite: 
Yes

The kimberlites of the Premier Diamond Mine are traversed by carbonate dykes that have generated widely differing opinions as to whether or not they are carbonatites, while they have also been cited in the debate on the relationship between carbonatites and kimberlites. Wagner (1914) first described the dykes and he considered that the calcite had been introduced by hydrothermal solutions into dyke rocks resembling kimberlites. Daly (1925) was the first to suggest that they were truly igneous rocks. Descriptions and a review of interpretations of the dykes will be found in Robinson (1975). The dykes within the mine occur as a connected system of dyke-like bodies that grade into the ‘Black Kimberlite’ as well as apparently isolated dykes which cut sharply across enclosing ‘Grey Kimberlite’. The dyke rocks consist of calcite, serpentine and magnetite with accessory phlogopite, apatite, pyrite, chalcopyrite, perovskite and traces of ilmenite and garnet. Full petrographic descriptions are given by Robinson (1975) and analyses of ilmenite and spinel by Gaspar and Wyllie (1984) who show that they have chemical characteristics similar to those of these minerals in carbonatites. Rock analyses are given by Verwoerd (1967).

Age: 
207Pb/206Pb determinations on galena from calcite-filled fractures and veins cutting kimberlite indicate an age of 1750±100 Ma for the kimberlite pipe itself, which must represent a maximum age for the carbonatitic dykes (Allsopp et al., 1967).
References: 

ALLSOPP, H.L., BURGER, A.J. and VAN ZYL, C. 1967. A minimum age for the Premier kimberlite pipe yielded by biotite Rb-Sr measurements, with related galena isotopic data. Earth and Planetary Science Letters, 3: 161-6.DALY, R.A. 1925. Carbonate dikes of the Premier Diamond Mine, Transvaal. Journal of Geology, 33: 659-84.GASPAR, J.C. and WYLLIE, P.J. 1984. The alleged kimberlite-carbonatite relationship: evidence from ilmenite and spinel from Premier and Wesselton Mines and the Benfontein Sill, South Africa. Contributions to Mineralogy and Petrology, 85: 133-40.ROBINSON, D.N. 1975. Magnetite-serpentine-calcite dykes at Premier Mine and aspects of their relationship to kimberlite and to carbonatite of alkalic carbonatite complexes. Physics and Chemistry of the Earth, 9: 61-70.VERWOERD, W.J. 1967. The carbonatites of South Africa and South West Africa. Geological Survey of South Africa, Handbook, 6: 1-452WAGNER, P.A. 1914. The diamond fields of southern Africa. The Transvaal Leader, Johannesburg.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith