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| Diamond Geology Published on www.debeersgroup.com Index A) Classification and genetic models B) Exploration...Sample Treatment D) World Production E) South African Diamond Occurrences 1. Large Kimberlite Mines 1...Koffiefontein 2. Smaller mineralised kimberlites in South Africa 2.1 The Oaks 2.2 The Zebediela Kimberlites 2...Terms Diamond Geology Page 2 www.debeersgroup.com A) CLASSIFICATION AND GENETIC MODELS Diamond deposits... their relative production contributions in South Africa were, primary (kimberlite) 8.63 million carats |
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| Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa e-mail: David.R.Bell@asu.edu ...University of Cape Town, Rondebosch 7700, South Africa Email: © 2004 Geological Society of South Africa ABSTRACT...subcontinental lithospheric mantle of southern Africa, and may be used to probe its compositional structure...garnet megacrysts from 61 kimberlites in southern Africa define four broad arrays on the basis of Cr2O3...mantle. High-Cr megacrysts in kimberlites of the northern cratonic areas bear the influence of lithospheric |
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| e g e o r ev Kimberlite-hosted diamond deposits of southern Africa: A review Matthew Field a,⁎, Johann...Southdale, 2135, South Africa c De Beers Group Services, PO Box 47, Kimberley, South Africa d De Beers Canada...April 2008 Keywords: Diamond Kimberlite Diatreme Pipe Dyke Mantle-xenolith Diamond-inclusion A B S T R...discovery of diamonds in river deposits in central South Africa in the mid nineteenth century, it was at Kimberley...economic and industrial development of southern Africa. Following the discoveries at Kimberley, even more |
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| Ultramafic nodules from the Kimberley pipes, South Africa F. R. BOYD Geophysical Laboratory, Carnegie...collected in a number of other areas in southern Africa in two important respects: (1) There are no sheared...mosaic-porphyroclastic. In most nodule suites from southern Africa and elsewhere in the world, these low-temperature...low-temperature. mainly coarse peridotite xenoliths from northern Lesotho and other areas. Abundant sheared dunites...coarser than that of the granular peridotites from northern Lesotho. COX er al. (1973) gave 2-7 mm as the |
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| 3, 223-235. The physical pmperti~ of garnet in diamond-kyanite-eclosite and diamondcorundum-eclogite ~te...garnet in six newlir available diamond eclosites. Garnets from diamond-bearing eclosites do not constitute...of New South Wales, ,4mtra//a; Morna Mathim, Divi6on of Geologiral Sciences, Uni~rsity oj Cape To~n, Rondebosch...Rondebosch, C. P. South Africa. Introduction Ultt ~mafic xenoliths, which do not resemble any rocks...(1967).Of the many types of these xenoliths, the diamond-bearing eclogites are among the most r~re, and |
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| Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa Department of Earth, Atmospheric...and Proterozoic lithospheric terranes in southern Africa during the Mesozoic was evaluated by thermobarometry...thick off-craton lithosphere capable of hosting diamond. This inference is supported by U – Pb thermochronology...day distribution of surface heat flow in southern Africa is related to this dynamic event and is not a direct...cratons, of which the Kaapvaal craton of southern Africa is a well-studied example (De Wit et al., 1992) |
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| S. R. Hart, I. D. MacGregor, R. H. Mitchell, D. Smith, J. Ro Smyth, H. Go Wilshire The MantleSample...mechanismsof diatreme formation, and the parageneses of diamond will find much to excite them in Volume I of these...development since the First Kimberlite Conference, held in Cape Town in 1973, has come in the interpretation of...FROM 15 KIMBERLITES A Diamond-Graphite Ecologite From the Roberts Victor Mine, C. J. Hatton and John...Gurney ........................................ Diamond and Graphite in Eclogite Xenoliths From Kimberlite |
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| geology; as a result I have not attempted to describe diamond prospecting and mining and, although I have attempted...Mitchell, A. Nicolas, D.J. Powell, A.M. Reid, J.V. Smith, N.V. Sobolev, W.E. Stephens, and P.J. Wyllie. In...John Gurney and Joe Smith with whose research groups at the universities of Cape Town and Chicago I have...collaboration. Much of my fieldwork in southern Africa has been carried out with the cooperation and assistance...7.3 2.8 2.9 Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . West Africa . . . . . . |
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| model for the origin of ilmenite in kimberlite and diamond: implications for the genesis of the discrete nodule...kimberlite event itself, and would represent a third diamond paragenesis, distinctly younger than those related...mineral in many Group I kimberlites (defined by Smith 1983), occurring in a variety of different associations...kimberlites (e.g. Monastery (Gurney et al. 1979) and Frank Smith (Pasteris et al. 1979)). These large grains are...pyroxene-ilmenite xenolith from the Weltevreden mine, which they suggest is also genetically related |
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| SPINEL MACROCRYSTS FROM KIMBERLITES IN SOUTHERN AFRICA DANIEL J. SCHULZE§ Department of Geology, University...single-crystal macrocrysts in kimberlites from southern Africa (approximately 1500 grains from 20 kimberlites...from a variety of mantle xenoliths from southern Africa and North America (approximately 150 xenoliths)...Unusually Fe- and Ni-rich macrocrysts unique to the Lace mine are from Fe-rich orthopyroxene-bearing peridotites...kimberlite, chromian spinel, magnesiochromite, southern Africa. SOMMAIRE Je présente ici une comparaison, en |
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| GPa as estimated from the calibration curves. Local determination of F in adjacent grains is possible...in The xenoliths from the kimberlite pipes in Northern Lesotho at the southern margin of the Archean...different pipes to construct a single geotherm for Northern Lesotho, which is a good start toward establishing...al. [8] on the relative stability of graphite (diamond) under upper mantle conditions to gether with...Ρ equilibrium conditions for xeno liths from Northern Lesotho kimberlite pipes: 1) Tava Putsoa; 2) Letseng |
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| l ..,_ • ••' f..J r) THE GENESIS OF T H E DIAMOND By ALPHEUS F. WILLIAMS, B.Sc. GENERAL MANAGER...of the rise and development of the diamond mines of South Africa, from an historical, economic and technical...account of the development of the De Beers group of diamond mines, together with an account of the famous people...played such a great part in the development of the diamond industry and at a later date in the development...the diamond fields when the mines in the Kimberley and Jagersfontein areas were the only diamond mines |
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| SURVEY OF SOUTH AFRICA COUNCIL FOR GEOSCIENCE GEOLOGICAL SURVEY OF SOUTH AFRICA MINERALOGY OF SOUTH AFRICA:... COUNCIL FOR GEOSCIENCE GEOLOGICAL SURVEY OF SOUTH AFRICA Scientific Editor R.D. Dixon Linguistic and...Council for Geoscience (Geological Survey of South Africa), 280 Pretoria Street, Silverton, Pretoria or........................... 69 5.1 Overview of South African Occurrences ..............................LAYEREDSUITE,BUSHVELDCOMPLEX.... 111 MINERALOGY OF SOUTH AFRICA: TYPE-MINERAL SPECIES AND TYPE-MINERAL NAMES |
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| Geological Sciences, University of Cape Town, Rondebosch, South Africa (Received November 9, 1999; accepted...mantle sources) worldwide (North America, southern Africa, Australia) are restricted (␦18OVSMOW ⫽ 5.24‰,...(from “enriched” mantle, and restricted to southern Africa) have anomalously high 18O/16O ratios (␦18OVSMOW...unmodified [host] kimberlite source compositions” (Smith et al., 1995). High equilibration temperatures of...suites. Localities represented are Monastery, Frank Smith, Kelsey Lake, Iron Mountain #26, Lekkerfontein |
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| the palaeogeotherm in the upper mantle beneath northern Lesotho was inflected in late Cretaceous times...cratonic areas, including Lesotho, Premier, Frank Smith, Siberia. Non-inflected geotherms beneath stable...1975), Mothae (Nixon and Boyd, 1973a; Dawson and Smith, 1975; Mori, 1975), Thaba Putsoa (Nixon and Boyd...depth-temperature relationships in the upper mantle beneath northern Lesotho at late Cretaceous times (G.L. Davis et...Ringwood, 1970). The diamond-bearing garnet lherzolite BD2125 (Dawson and Smith, 1975) equilibrated at |
 | HANSON, E.K., MOORE, J.M., BORDY, E.M., MARSH, J.S., HOWARTH, G., ROBEY, J.V.A. (2009) CRETACEOUS EROSION IN CENTRAL SOUTH AFRICA: EVIDENCE FROM UPPER-CRUSTAL XENOLITHS IN KIMBERLITE DIATREMES. South African Journal of Geology, 112 (2) 125-140 doi:10.2113/gssajg.112.2.125 | Journal (article/letter/editorial) |
| A. ROBEY 125 CRETACEOUS EROSION IN CENTRAL SOUTH AFRICA: EVIDENCE FROM UPPER-CRUSTAL XENOLITHS IN KIMBERLITE...Rhodes University, P.O. Box 94, Grahamstown, South Africa email: emilykhanson@gmail.com; j.moore@ru.ac...Kimberley, South Africa email: jock.robey@debeersgroup.com © 2009 June Geological Society of South Africa ABSTRACT...fourteen Group I kimberlite diatremes in central South Africa were examined for upper crustal xenoliths in...eruption (~85 Ma), they were restricted to the south-eastern half of the study area. At the latter time |
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| and that Fig. 1. Structural units of southern Africa, as discussed in this paper, superimposed on a...studies of xenoliths from its many productive diamond mines and from other kimberlites. More data probably...from kimberlites and some alluvial deposits of local derivation; over 3400 Cr-pyrope garnets from more...temperature for each grain can be referred to a local paleogeotherm to estimate the depth from which the...(Finnerty and Boyd, 1987), which roughly parallels the diamond– graphite stability curve. This procedure may underestimate |
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| CRYSTALS NOT PISTOLS THE GENESIS OF T H E DIAMOND 'By ALPHEUS F. WILLIAMS, B.Sc. GENERAL JIIANAGER...INCLUSIONS FLOW STRUCTURE THE CHAPTER XIII DIAMOND THE CULLINAN DIAMOND THE VALUE OF THE CARAT-WEIGHT CHARACTERJSTICS...THE DIAMOND - CARDON AND GRAPHITE 403 403 403 404 410 425 420 FOREIGN INCLUSION:! IN DIAMOND BROKEN...444 THE CRYSTALLOGRAPHY OF THE DIAMOND FORM AND STRUCTURE OF THE DIAMOND CRYSTALLIZATION THE TETRAHEDRON...TWL'INING CHAPTER PHYSICAL PROPERTIES OF THE DIAMOND - 448 449 450 455 4 60 XV CLEAVAGE-FRACTU |
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| from 16 intrusions in Lesotho, the Republic of South Africa, and Tanzania have been investigated. The following...properties of the kimberlitic zircons and the diamond grade of their host rocks. Introduction Zircon...bronzite that are found in the kimberlites of northern Lesotho also show some fractures and cracks (NlxoN...the abundance of zircon in the Kimberley and Frank Smith mines, he admitted that zircon may possibly be...kimberlite. Zircon has been recorded as inclusions in diamond (MEYER and SVlSERO 1973) and magnesian ilmenite |
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| ftjsXL'vvv^ rmf ' j^lr ^1 THE DIAMOND MINES OF SOUTH AFRICA VOL. II Digitized by the Internet...org/details/diamondminesofso02will THE DIAMOND MINES OF SOUTH AFRICA BY GARDNER F. WILLIAMS, M.A. GENERAL...Washing and Crush- Ground. the Diamonds The Diamond Sorter. . . i of the Blue Pulverization ...Storing and Handling of Dynamite. The Fire in De Beers Mine, iith July, 1888. The Occurrence of “Mud Rushes...Many An Village. Drawbacks. Formation of the Diamond . stone. Sir Stelzner. Locusts. . . Professor |
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| Hawthorne, Bram Janse, Mal McCallum, Barbara Scott Smith, Simon Shee, Mike Skinner, Bruce Wyatt, and Peter............................... 126 5.3.3.2. West Africa ........................................... 126...15. 6.6.3 .1. Diverse South African Kimberlites (Dawson and Smith 1975, Smith et al. 1978) . . . . .......................... 6.6.3.5. Orroroo (Scott Smith et al. 1984) ......................... 6.6.3.6....Greenland (Emeleus and Andrews 1975, Scott 1981, Scott Smith et al. 1983) . . . . . . . . . . . . . . . . . |
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| FOR DIAMOND-BEARING KIMBERLITES"* A.R. NEWTON Geology Department, University o f Cape Town, Cape Town...Town (South Africa) and J.J. GURNEY Geochemistry Department, University o f Cape Town, Cape Town (South...(South Africa) Received March 11, 1975 Sharp has proposed an origin for kimberlites involving plate tectonics...tectonics and has used South Africa as the main example. This hypothesis is open to criticism from both...tendency for it to rebound. (2) The concept of the Cape Fold Belt as representing a subduction zone is probably |
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| stationery while vacationing on the Natal Coast of South Africa. Wilson uses it as a symbol of the Ivory Coast...Coast. DIAMONDS: FROM BIRTH TO ETERNITY A diamond is rarely found embedded in kimberlite rock. This...update its diamond mining and reeovery inlormation, we asked the assistance ol John Roux, Diamond Information...blood, my father (a distinguished editor ol the Cape Times) having been one ol lour sons ol a sullragan...to present Arthur Wilson’s compilation on the diamond and its origins. Richard T. Liddicoat, Jr. CONTENTS |
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| isotopically distinctive Group I kimberlites recognized by Smith (1983), which broadly correspond to the basaltic...Jagersfontein (Hops et al. 1989, 1992) in southern Africa. (The locations of these and other southern African...clinopyroxene megacrysts, which they termed ‘‘Granny Smith’’ diopsides, from Jagersfontein and a number of...‘‘Granny Smith’’ diopside suite is also present in the Nouzees kimberlite in North-West Province, South Africa...and 2 kimberlites); 2 Nouzees; 3 Weltevreden-Frank Smith; 4 Kimberley cluster (Bultfontein, de Beers, |
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| TR ClI- 27 THE ALLUVIAL DIAMOND DEPOSITS OF THE LOWER VAAL RIVER BETWEEN BARKLY WEST AND THE VAAL-HARTS...VAAL-HARTS CONFLUENCE IN THE NORTHERN CAPE PROVINCE, SOUTH AFRICA By FABRICE GILBERT MATHEYS B.Sc. (Hons)...Grahamstown DECEMBER 1990 ABSTRACT The between diamond deposits along the Vaal River, alluvial Barkly...at most of these mineral s are locally derived. Diamond grade variations within the Younger Gravels are...Alluvial the tectonic the by channel width and diamond exploration setting, the palaeo- stability |
