 | | Journal (article/letter/editorial) | | bodies Roger N. Scoon PO Box 2461, Rivonia 2128, South Africa e-mail: rnscoon@iafrica.com Andrew A. Mitchell...4000, South Africa e-mail: mitchell@pixie.udw.ac.za © 2004 Geological Society of South Africa ABSTRACT...are emplaced in the Upper Critical zone, the Onverwacht and Twyfelaar pipes occur in the Lower Critical...evaluation and mining of the Driekop, Mooihoek and Onverwacht pipes, which are among the oldest platinum mines...comparatively deep-rooted, stock-like bodies. At Onverwacht and Twyfelaar, the stocks are rimmed by irregular |  | | Journal (article/letter/editorial) | | FROM THE ONVERWACHT AND TWEEFONTEIN ULTRAMAFIC PIPES, EASTERN BUSHVELD COMPLEX, SOUTH AFRICA FEDERICA...Witwatersrand, PO Wits 2050, South Africa ABSTRACT The ultramafic pipes of Onverwacht and Tweefontein, in the...the eastern part of the Bushveld Complex, in South Africa, contain small xenoliths of chromitite that...Complex, Republic of South Africa. SOMMAIRE Les pipes ultramafiques de Onverwacht et Tweefontein, dans...The Merensky Reef in the Bushveld Complex, in South Africa, was discovered at about the same time (1924) |  | | Report (issue) | | 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 |  | | Journal (article/letter/editorial) | | REPLACED MERENSKY REEF AT THE AMANDELBULT MINE, SOUTH AFRICA R.N. SCOON Department of Geology, Rhodes...Rhodes University, Grahamstown 6140, South Africa e-mail: rnscoon@iafrica.com A.A. MITCHELL School of Geological...4000, South Africa e-mail: mitchaa@mweb.co.za © 2011 March Geological Society of South Africa ABSTRACT...in the eastern limb of the Bushveld Complex, South Africa, differ sufficiently from one another to warrant...In our previous contributions on the Driekop, Onverwacht, and Twyfelaar localities we noted that despite |  | | Journal (article/letter/editorial) | | hortonolitedunites, and dunite-bronzitites from the Onverwacht,Mooihoek,and Driekoppipesrevealedthe presenceof... mineralsof the pipes. the three dunRe pipes,Onverwacht,Mooihoek,and The unique geologicalpositionof...the Introduction ton Pt were encountered at Onverwacht and annual productionfrom the three pipeswason...pipeswason the order of 15,000 ozs. Driekop was the last mine to ceaseoperationsin 1961. The disappearanceof these...connection"implied magmaticassociation, it also, The pipesof Onverwacht,Mooihoek,and Driekop and even better, fits the |  | | Journal (article/letter/editorial) | | GEOLOGICAL EXCURSION TO THE MINING AREAS OF SOUTH AFRICA by Aberra Mogessie, Christoph Hauzenberger...Department of Geology, University of the Free State, South Africa 1. Preface Almost a year ago Aberra Mogessie...(where we had organized past excursions) and South Africa. Having discussed the matter with Christoph...areas of South Africa. We contacted Christoph Gauert from the University of Free State, South Africa to help...help us with the local organization especially to get permission from the different mining companies to |  | | Journal (article/letter/editorial) | | 155 THE PRINCIPAL GEOLOGICAL FEATURES OF THE ONVERWACHT PLATINIFEROUS DUNITE PIPE, EASTERN LIMB OF THE...Geology, Rhodes University, Grahamstown 6140, South Africa e-mail: rnscoon@iafrica.com A.A. MITCHELL Department...Durban 4000, South Africa e-mail: mitchaa@mweb.co.za © 2010 June Geological Society of South Africa ABSTRACT...ABSTRACT The Onverwacht pipe, situated on the leasehold of Eastern Chrome mines in the eastern limb of the...as it is the site of the oldest platinum mine in South Africa. The central part of the pipe consists of |  | | Journal (article/letter/editorial) | | the eastof the pipe.Dunitc to the west of the Onverwacht hortonolite core has a layeredstructurewith...that olivine in Driekop (D), Mooihoek(M), and Onverwacht(O) platiniferous the outer portionsof the Onverwachtpipe...able amountsof platinum,but the restof the pipe mine concentrates of platinum-groupmineralsfrom was practicallybarren...mobilecomponents were matitic veinsof hortonolite,amphibole,phlogopite, transported.This paper emphasizesthe chemicalasand...holelogs,and detailedunderground samplingof the The Onverwacht pipe containeda broken-up dunite and countryrock |  | | Journal (article/letter/editorial) | | gruneritic Archean gold deposit, Barberton, South Africa Patrick J. Williams ) National Key Centre...Abstract The Lily mine, located some 24 km northeast of Barberton in South Africa, occurs stratabound...Archean; metamorphism; grunerite; Barberton; South Africa 1. Introduction Stratabound deposits in Fe-rich...Barberton granite–greenstone association in southern Africa contain an exceptional concentration of gold deposits...greenstone belt showing the location of the Lily mine. ŽSimplified from Anhaeusser et al., 1983 and de |  | | Journal (article/letter/editorial) | | University of the Witwatersrand, PO Wits, 2050, South Africa CHRISTOPHER A. LEE¶ Anglo Platinum Geology...Department, PO Box 62179, Marshalltown, 2107, South Africa ROBERT P. SCHOUWSTRA Anglo Platinum Research...1412, South Africa PETER MELLOWSHIP Impala Platinum Mines, PO Box 5683, Rustenburg, 0300, South Africa...and eastern limbs of the Bushveld Complex, in South Africa. Grades for the mined reef interval are uniform...km of strike length, at 5–7 g/t, except for Union mine, where it is currently 8 g/t. The relative proportions |  | | Journal (article/letter/editorial) | | immediately surrounding Bushveld rocks, followed by local redistribution of Pb by whatever fluid was present...stretches from the Mpumalanga and Limpopo Provinces of South Africa in the east to the Northwest Province... , 30°30 , 30°00 Middelpunt mine Hackney mine , 24°30 Steelpoort fault Transvaal Supergroup Bushveld...show the location of the Bushveld Complex in South Africa and the eastern Bushveld in context of the entire...extending from the Oliphants River valley to the Steelpoort fault, 70 km along strike to the southeast. Most |  | | Journal (article/letter/editorial) | | values of coexisting garnet, clinopyroxene and phlogopite for twelve compositionally and texturally diverse...the eclogites and resulted in the formation of phlogopite, amphibole and celsian. The 8~XO value of the...correlation between the isotopic composition of phlogopite and the primary pyroxene and garnet. The large...Introduction: The Roberts Victor kimberlite pipe in South Africa is well-known for its diamond production and...and often extensive. This alteration occurs as phlogopite-rich veins and as fine-scale alteration of the |  | | Book | | APPRECIATION R. M. Shackleton THE STRUCTURAL FRAMEWORK OF AFRICA Xi 1 T. N. Clifford ARCHAEAN VULCANICITY AND...KIBARIDE AND KATANGIDE OROGENIC BELTS OF CENTRAL AFRICA 97 L. Cahen OROGENIC AND POST-OROGENIC PLUTONISM...SOUTHERN AFRICA 157 O. Von Knorring LATE PALAEOZOIC TO RECENT IGNEOUS ACTIVITY IN WEST AFRICA AND ITS...CONTENTS 12 VULCANICITY AND RirT TECTONICS IN EAST AFRICA B. C. King 13 TECTONIC AND MAGMATIC EVOLUTION...OF DYKES AND RELATED IRRUPTIVE ROCKS IN EASTERN AFRICA 337 \ J. R. Vail 17 GEOCHEMICAL VARIATIONS IN |  | | Journal (article/letter/editorial) | | hydrosphere. INTRODUCTION In the Matagami mining district of Quebec, Canada, economically important Zn--Cu...greenstone belt (Goodwin and Ridler, 1970). In this district the massive sulphides occur above felsic volcanics...Zn--Cu sulphide deposits in the Matagami mining district of Quebec Sample 1 2 3 4 5 6 SiO2 (wt....that this process involved the development of phlogopite and stilpnomelane, substantiating the geochemical..."sediments" in Archaean regions include Agnico--Eagle gold mine, Joutel, Quebec and the Amulet A ore body, Noranda |  | | Book | | Barberton Greenstone Belt, Kaapvaal Craton, South Africa ................................ 7.1 The Barberton...Belt, Eastern Kaapvaal Craton............ 7.1.1 Onverwacht Group ...................................................................... 9.2 Evolution of South Indian Granite-Greenstone Terrains ...............nuclei documented in the eastern Kaapvaal Craton, South Africa, and the Pilbara Craton, northwestern Australia...surface area on Moon Significant events 0 Crater South Ray 1 Crater Copernicus ~3.26-3.22 Ga Barberton |  | | Book (edition) | | Southern Africa a Collector’s Guide ■ Rocks, Minerals and Gemstones of Southern Africa & — - ... T ~ '' .rats en&nes L of Southern Africa A Collector’s Guide - Struik Publishers (an operating...typical accessory mineral from the world famous Tsumeb mine Overleaf: Crystalline incrustations of vanadinite...suggestions and advice. Author’s Preface Southern Africa has much to offer the amateur geologist, whatever...best plan is to take local advice wherever you are. 9 In small places try the local police station first |  | | Journal (article/letter/editorial) | | 4-65 ppb) by Moiseenkoet al. (1971), and from South Africa (10-20 ppb) by Vilioen et al. (1969). A preferredassociation...iron-formationcollectedfrom the Archean greenstone belts of South Africa. Researchon the goldcontentsof mineralsindicates...Dyke • Witwaterarand Basin ..... BOTSWANA AFRICA _._ .... ./ PRETORIA t ,.'• Pongola Group •i•...GreenstoneBelt ß Au25*ppb,ß Au4-25ppb,, AuO-4ppb South Afticon Greenstone Belts ß Au25*pith,•Au 4-25ppb...andchalof phlogopite-peridotite, hornblende-peridotite, and copyrite. amphibolite.The phlogopite-peridotite |  | | Journal (article/letter/editorial) | | tectonics, magmatism, and mineralisation of the South African Precambrian shield is discussed. A geosynclinal...five times as long as the post-Precambrian. The South African shield appears highly suitable for investigations...preserved and well exposed. The Precambrian in southern Africa comprises a more or less continuous suite ofmetasediments...of more than 35,000 m. Furthermore, in southern Africa the earth's history, at least in outline, appears...mineralisation. There is hardly anywhere else in Africa an orogenic zone to which this applies. Recent |  | | Journal (article/letter/editorial) | | concentrates originating from the Driekop platinum mine, South Africa, collected and first described by E. F. Stumpfl...interpretation of Rudashvesky et al. (1992) for the Onverwacht and Mooihoek pipes: a high-temperature magmatic...of discovery are summarize d in Table 1. The Onverwacht platiniferous pipe is the type locality of tetraferroplatinum...crosscutting the Upper Critical Zone, and the Onverwacht and Twyfelaar pipes in the Lower Critical and...(Driekop, Mooihoek), or by magnesian harzburgite (Onverwacht, Twyfelaar). The PGE mineralization is concentrated |  | | Journal (article/letter/editorial) | | 255 KT 2Q Hendriksplaots 281 KT 24'30' 21, Onverwacht 292 KT 22. Doombosch 294 KT 23, 24, Winterveld...purealbite,puremicrocline,and anorthite plagioclase, phlogopite,alkalifeldspar,and quartzare glass,wasusedto...Plagioclase, bronzite,augite, (Cameron,1977). phlogopite,alkali feldspar,and quartzoccuraspostFor modalanalysis...Figure 2. The unitextends from Zeekoegat to Steelpoort, ranging from 85 to 65 m in thickness. Noriresof...presentin certain intervals.At certainlocalities(e.g.,Onverwacht,Moeijelijk),slump structuresare prominent(Cameron |  | | Journal (article/letter/editorial) | | will dooument data from different regions to avoid local anomalies. Data from recent volcanic rocks are ...1966) and South Africa (AT.LSOXV et aE., 1968). Common lead data am available from South Africa only and...by ALLSOPP et aZ. (1968). Rb-Sr dating of the Onverwacht series,the oldest member of the * Pb=/Pb=P =...basis of field geology, to be younger than the Onverwacht series (HUNTER, 1957). It thus appears that the...(1969) on sulfides and a single zircon from the Onverwacht and HURLEY et al. (1971) have reported a Rb-Sr |  | | Journal (article/letter/editorial) | | Mineralization in Hortonolitic Dunites of the Mooihoek and Onverwacht Pipes, Bushveld Complex N. S. Rudashevsky 1,...platiniferous hortonolitic dunites of the Mooihoek and Onverwacht pipes, Bushveld Complex, show the following PGM... in den Horthonolit-Duniten der Mooihoek und Onverwacht Pipes, Bushveld-Komplex Minerale der Platingruppe...Platin-fiihrenden Hortonolith-Duniten der Mooihoek und Onverwacht-Pipes, Bushveld-Komplex, fiihren die folgenden...Mineralization in Hortonolitic Dunites of the Mooihoek and Onverwacht Pipes 39 metasomatischer Beeinflussung bei |  | | Journal (article/letter/editorial) | | Alkaline Intrusive Rocks from Bitterfontein, South Africa J.R. McIver Department of Geology, University...University of the Witwatersrand, Johannesburg, South Africa Abstract. Cretaceous alkaline intrusive rocks present...intrusives occurring in a broad zone parallel to the south western African coastal regions. This paper presents...especially of phlogopite is important in the generation of members of the Bitterfontein suite. Phlogopite fractionation...(Jansen 1960) from the area around Bitterfontein, South Africa (Fig. 1). These rocks are spatially associated |  | | Journal (article/letter/editorial) | | 98195 ABSTRACT Compositional data on apatite, phlogopite, and amphibole indicate that the high-temperature...Zone are from the Rustenburg Platinum Mine and Western Platinum Mine in the western Bushveld Complex, but...olivine-rich rocks containing abundant interstitial phlogopite. In some cases, these apatite grains are several...millimeters in diameter and contain inclusions of phlogopite, monazite, and pargasitic hornblende (Fig. IB)...Critical Zone rocks is typically associated with phlogopite. In several Bushveld samples, Downloaded from |  | | Book | | University of the Witwatersrand, Johannesburg, South Africa D. BRIDGWATER Gr0nland Geologiske Unders@gelse...of Natal, PO Box ·375, Petermaritzburg 3200, South Africa G. A. L. JOHNSON Department of Geology, Science...SUTTON Department of Geology, Imperial College, South Kensington, Lond?n SW7 2A Y, England D. H. TARLING...Southern Paralic Shelf Alpine Belt . Form of the South European Plate Russian Platform and Donets Basin...southern Africa and Australia. The occurrence of komatiite flows in the Barberton Mountains of South Africa |
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