 | | Journal (issue) | | Geological Society of Zimbabwe G Z S Newsletter October 2015 No. 3 of 3 of 2015 Heavy mineral concentrate...concentrate (Total weight 4.974g) from the Somabula alluvial deposit. One diamond crystal (octahedron/dodecahedron)...alexandrite, sapphires, garnet, amethyst, topaz (“Somabula blue” and white), aquamarine, boart and native...Society of Zimbabwe, P.O. Box CY 1719, Causeway, Harare Geological Society of Zimbabwe Newsletter ... ARTICLES AND REPORTS A Review of Diamonds in Zimbabwe – a Century On .............................. |  | Oberthur, T., Weiser, T. W., Gast, L., Schoenberg, R., Davis, D. W. (2002) PLATINUM-GROUP MINERALS AND OTHER DETRITAL COMPONENTS IN THE KAROO-AGE SOMABULA GRAVELS, GWERU, ZIMBABWE. The Canadian Mineralogist, 40 (2) 435-456 doi:10.2113/gscanmin.40.2.435 | Journal (article/letter/editorial) | | DETRITAL COMPONENTS IN THE KAROO-AGE SOMABULA GRAVELS, GWERU, ZIMBABWE THOMAS OBERTHÜR§ Bundesanstalt für...the Somabula gravels, a paleoplacer of Upper Karoo (Triassic, ~200 Ma) age near Gweru, Zimbabwe. The...The polymict spectrum of heavy minerals in the Somabula placers comprises staurolite, zircon, monazite,...derived from late Archean greenstone belts of the Zimbabwe craton. Keywords: zircon, monazite, tantalite...isotopes, paleoplacer, Karoo Formation, Somabula gravels, Gweru, Zimbabwe. SOMMAIRE Nous avons étudié des concentrés |  | | Journal (article/letter/editorial) | | Ijebu Series, has so far been found only in that district of the Lagos Province. These beds are extensively...group of phyllites and grits altered into garnet, andalusite, and staurolite-schists, and hornfels, with the...might truly include the schists of the entire district. Typical specimens of the granites, pegmatites...last-named showed 67'77 per cent, of iron-peroxide. The district is compared with the Oban Hills of the Eastern...Sartorite by Dr. Trechmann. OOEEB8PO1TDENCE. THE SOMABULA DIAMOND FIELD. SIB,—I notice in your December |  | | Journal (article/letter/editorial) | | Sartorite by Dr. Trechmann. OOEEB8PO1TDENCE. THE SOMABULA DIAMOND FIELD. SIB,—I notice in your December...issue ' a comment by Dr. Flett on my paper on the Somabula Diamond Field, and I take this opportunity of...showing the characteristic angles of staurolite. Andalusite may also be added to the list of what I have...after a review of all the facts, firstly, that the Somabula diamonds, as also those of Brazil, India, and |  | | Journal (article/letter/editorial) | | few of the intensely sheared rocks of such a district, except very locally--a few yards, for instance...Rifle Kopje, near Bulawayo; Red Hills, Victoria district). In other cases they occur as well-marked dykes...contact-alteration products, one may observe minerals such as andalusite and sillimanite (fibrolite). The l',tter occurs...situated on the Banded Ironstone Series, and andalusite (or rather, perhaps, chiastolite)-schist underlies...sequence. I t is in the somewhat remote Lomagundi district that these beds have attracted most attention |  | | Journal (article/letter/editorial) | | successions are noted, viz. 12 km in the Bulawayo District (Amm, 1940), 24 km at Hunters Road, Gwelo (Macgregor...2), from extremely low grades typical o f t h e midlands region, to highest grades that circumscribe and...in Table I and emphasized by the occurrence of andalusite, cordierite--anthophyllite and lack of garnet...chloritoid, actinolite, garnet, pyrophyllite, andalusite and epidote. Kyanite is rare (Zones 2b--3b)....amphibolite facies Anthophyllite, cordierite, corundum, andalusite, sillimanite and grunerite are typical. Garnet |  | | Journal (article/letter/editorial) | | Notes on, L. F. Spath, 27, 65, 115, 170, 220. Andalusite(ChiastoKte), A. Brammal], 383. Appendages of...498. Barke, F., Carboniferous Limestone, Wrekin District, 384. Barnacles, Lepadid, Derivation of, J. M...of Scania, G. T. Troedsson, 35. Brammall, A., Andalusite (Chiastolite), etc., 383. British Association...New, R. G. Carruthers. 436. Limestone of Wrekin District, L. M. Parsons, 77; F. Barke, 304. Carruthers...and Pitcairn, 131. Maufe, H. B., Platinum in the Somabula Gravels, 520 ; Rhodesian Geology, 429. Maury, |  | | Journal (article/letter/editorial) | | absent, giving place to hornblende. Biotite, andalusite, and cordierite are common. Still farther afield...Wagner, "The Geology of a Portion of the Belingwe District," Trans. Geol. Soc. of S.A., xvii, 1914, 39-54...Gravels of the The Red Rock at Hunstanton. 29 Somabula Forest," S.R.G.S. Bulletin, No. 8, pp. 13-14; |  | | Journal (issue) | | the writer in r9r9 in the Triassic gravels of Somabula. Gorceixite was originally described by E. Russak...The following description was published of the Somabula material : 2 '' ' Beans.' A very interesting constituent...Geology of the Diamond-bearing Gravels of the Somabula Forest by A. M. , Macgregor ; Southern Rhodesia...streaky in dark cream and cafe.-au-lait colours. The Somabula gravels have not been worked during the last twelve...within the Rhodesian Stor1nberg series. 1 In the Somabula Forest the diamond-bearing wash rests upon the |  | Melcher, Frank, Graupner, Torsten, Gäbler, Hans-Eike, Sitnikova, Maria, Henjes-Kunst, Friedhelm, Oberthür, Thomas, Gerdes, Axel, Dewaele, Stijn (2015) Tantalum–(niobium–tin) mineralisation in African pegmatites and rare metal granites: Constraints from Ta–Nb oxide mineralogy, geochemistry and U–Pb geochronology. Ore Geology Reviews, 64. 667-719 doi:10.1016/j.oregeorev.2013.09.003 | Journal (article/letter/editorial) | | NU 4.1.2. Congo Craton (DRC) 4.1.3. Zimbabwe Craton (Zimbabwe) 4.1.4. Kaapvaal Craton (South Africa)...Mineralogy 4.3.2. Kamativi Schist Belt (western Zimbabwe) 4.3.3. Orange River Pegmatite Belt (Namibia,...Birimian TE 5.1.4. Kaapvaal Craton D 5.1.3. Zimbabwe Craton 5.2.2. North-eastern DRC 5.3. Neoproterozoic...(Democratic Republic of the Congo), the Kamativi Belt (Zimbabwe) and the Jos Plateau (Nigeria). Mn-rich columbite-tantalite...late-orogenic (e.g., West African Craton, MA Zimbabwe Craton), post-orogenic (Kibara Belt, Damara Belt |  | | Journal (article/letter/editorial) | | Unst, Shetland, '54, 399 Amisk-Athapapuskow Lake District, '20, (R) 282 Ammonite, new Name for Lias, D....and the Baltic Breach, H. H. Howorth, '05, 337 Andalusite and Chiastolite, R. H. Rastall, '15, 336 — and...Hemisphere, '39, 489 Jurassic Iron Ores, Cleveland District, '42, (R) 207 ; Chloride Waters of Great Britain...Perthshire, Unusual, W. T. Harry, '52, 41 Appleby District, Geology of, '15, (R) 431 ; '42,(R)78; '52, (R)...70 Assynt Culmination, E. B. Bailey, '35, 151 — District, Geological Excursion Guide, '38, (R) 140 — Mountains |  | | Book | | ........................ 7.2 Evolution of the Zimbabwe Craton..........................................swarms are outlined in several terrains, including Zimbabwe Craton (Fig. 3.1), southern India (Fig. 3.2) and...Sebakwian swarms in the Selukwe and Mashaba areas of Zimbabwe (Stowe 1973) (Fig. 3.1), pre-3.4 Ga old Sargur...xenolith distribution patterns in the Mashaba area, Zimbabwe Craton: T tonalite, D granodiorite, A adamellite...reported from the Selukwe-Gwenoro Dam area, southern Zimbabwe (Stowe 1973; Taylor et al. 1991), where both across-strike |  | | Report (issue) | | Trail in Gilgit-Baltistan DUDLEY BLAUWET 58. Zimbabwe Blue Topaz: St. Anne's Mine JAN KANIS 60. Brazil:...Kleine Spitzkoppe, Namibia; Mokrusha Mursinka District, Ural Mountains, Russia; Paprok, Laghman Province...(Simmons et al., 1987). Other pegmatites in this district contain abundant primary fluorite but no topaz...Kleine Spitzkoppe NYF-pegmatites in the Swakopmund District of Namibia have been known to produce nearly perfect:...with a large central cavity Murzinka (Alabashka) district, central U ral Mountains, Russia Gunther Neumeier |  | | Report (issue) | | deposits of rich •d iamantiferous grav.els in th,e district around Akwatia, which is 5 miles S.E. of· Kade...Foting·aia., 6½ miles N.N.W. of Jajma in the Kono district, a11d there was a find near Kennema in 1931. The...the Kambui hills nea.r Kennema and Lago, Kennema district. Small frag·ments of ruby and sma,11 zircon crystals...quantities. Alluvia.I diamond was discovered in the Somabula fore.st west of Gwelo in 1903. The stones occur...S. Rhodesia for the year 1915 (1916), pp. 2-5. Somabula diamond fields of Rhodesia, by F. P. Mennell; |  | | Book | | Russia (Ural mountains), Zambia (Kafubu) and Zimbabwe (Sandawana)). Their study demonstrates how these...vividly coloured Mn-rich minerals (kyanite, green andalusite, garnet -grossular, and spessartine- and red-epidote)...(sulfides of Ag, Pb, Cu, and Zn) in the Charcas mining district, San Luis Potosi. The area is characterized by...(Figure 2). Colombia, Brazil, Zambia, Russia, Zimbabwe, Madagascar, Pakistan, and Afghanistan (Figure...17. Tsa da Gliza. South Africa: 18. Gravelotte. Zimbabwe: 19. Sandawana, Masvingo, Filibusi. Mozambique: |  | | Journal (article/letter/editorial) | | (heliodor, aquamarine), topaz, rhodolite garnet, andalusite, and also mixed up with considerable amounts...eluvial in the Rondonia tinwith beveled mining district, Brazil.detrital topaz from eluvial placer deposits...Rondonia tin mining edges, Brazil. (c) Anhedral district, Brazil. Two processes, tectonic uplift and unroofing...spinel, garnet, chrysoberyl, topaz, tourmaline, andalusite, kyanite, and zircon. Sri Lanka recovers a great...gravel beds in the upper Karoo are operated at Somabula, Zimbabwe, not only for diamonds, but also for topaz |  | | Book (edition) | | • .265 269 . Diopside, Enstatite Kyanite, Andalusite, Idocrase, EpiPrehnite, dote, Sphene, Axinite...typical French family pere, mere, et in the Jura district, all busily engaged; on fils — the table will...diamonds were bought and sold. The diamond-bearing district actually spread over a wide area on the eastern...km.) from Rio de Janeiro, in the Serro do Frio district of the State of Minas Geraes. The discovery naturally...and the continuous development of the diamond district in Brazil rendered it impossible to hoodwink the |  | | Book (edition) | | XXXII. Fire-Opal) . 269 Diopside, Kyanite, Andalusite, Idocrase, EpiSphene, Axinite, Prehnite, dote...et a more at a — , fils — in the Jura district, the table will be kind noticed described above...actually spread side Pinner in the bought were district eastern the known from Golconda India. ...was gold (129 km.) development of the diamond district Brazil rendered it Brazil, Small the discovery...something 1727 their to it Serro do Frio district of the excitement. great size the in stone |  | | Book (edition) | | staples. Even such barely commercial stones as andalusite, iolite, sphene, chrysoberyl, and some of the...garnets, and turquoise. However, what do we do with andalusite, diopside, and sphene? A material, to be considered...Ceylon. Rhodesia, and S.W. Africa: Sri Lanka, Zimbabwe, and Namibia, respectively. However, although...Mexico Sillimanite: Williamstown, Australia Andalusite: Minas Gerais, Brazil Pyrophyllite: North Carolina...MEASUREMENT AND SPECIFICATION 28 TABLE Adamite Andalusite Shape Location dark green light green 0.63 |  | | Book (edition) | | ENSTATITE (Green Garnet\ DIOPSIDE, KYANITE, ANDALUSITE, IDOCRASE, EPIPREHNITE, DOTE, SPHENE, AXINITE...typical French family pere> mere, et in the Jura district, all busily engaged on fils the table will be...diamonds were bought and sold. The diamond-bearing district actually spread over a wide area on the eastern...km.) from Rio de Janeiro, in the Serro do Frio district of The discovery naturally caused great excitement... Europe continuous development of the diamond district in Brazil rendered it impossible to hoodwink the |  | | Book (edition) | | ENSTATITE (' Green Garnet'), DIOPSIDE, KYANITE, ANDALUSITE, IDOCRASE, EPIDOTE, SPHENE, AXINITE, PREHNITE...French family--pere, mere, et .fi/s-in the Jura district, all busily engaged; on the table will be noticed...diamonds were bought and sold. The diamond-bearing district actually spread over a wide area on the eastern...km.) from Rio de Janeiro, in the Serro do Frio district of the State of Minas Geraes. The discovery naturally...and the continuous development of the diamond district in Brazil rendered it impossible to hoodwink the |  | | Book (edition) | | extensive fields in the prophetically named Kimberley district of Western Australia promise to be of world importance...have been cut as gems are those from Sandawana in Zimbabwe, where the pegmatite veins containing the emeralds...Figure 1.26 Emerald in pegmatite from Sandawana, Zimbabwe 30 The Ages of Gems About 2565 million years...Colombia and the Archaean (2600 Ma) deposits in Zimbabwe, emeralds have formed at many different times...rewarded this kind of investment in both Sandawana (Zimbabwe) and Itabira (Brazil). The mining of emerald focuses |  | | Journal (article/letter/editorial) | | Li2Al2(Si2O6)2·2(H2O) 10 42 15 Analcime Anatase Ancylite Andalusite Anglesite Anhydrite Anilite Ankerite Annabergite...Chromium deposits of this type in South Africa and Zimbabwe contribute to more than 90% to the world supply...subtypes (Bushveld, South Africa, Great Dyke, Zimbabwe, Muskox, Canada, Dore Lake, Australia, Campo Formoso...South Africa (Fe, Cr, and PGE) and the Great Dyke, Zimbabwe (Cr, PGE/PGM) in idealized cross sections and...chalcedony whose color comes from chromium is found in Zimbabwe and known as mtorodite or mtorolite (McLean, 1967; | | | Journal (article/letter/editorial) | | Li2Al2(Si2O6)2·2(H2O) 10 42 15 Analcime Anatase Ancylite Andalusite Anglesite Anhydrite Anilite Ankerite Annabergite...Chromium deposits of this type in South Africa and Zimbabwe contribute to more than 90% to the world supply...subtypes (Bushveld, South Africa, Great Dyke, Zimbabwe, Muskox, Canada, Dore Lake, Australia, Campo Formoso...South Africa (Fe, Cr, and PGE) and the Great Dyke, Zimbabwe (Cr, PGE/PGM) in idealized cross sections and...chalcedony whose color comes from chromium is found in Zimbabwe and known as mtorodite or mtorolite (McLean, 1967; |  | | Book | | apatite in a variety of hosts • biotite mica in andalusite, chrysoberyl, kornerupine and Sri Lanka sapphire...and emerald • rutile in corundum, quartz and andalusite • sphene in ruby and spinel • uraninite in Sri...mica and chlorapatite. The Sandawana emeralds of Zimbabwe show tremolite crystals which are more hair-like...the red to beryl and the green and yellow to andalusite. • IRON, which gives blue aquamarine, blue and...by heating in oils, the process being slow. Andalusite may turn pink from olive-green when heated; brown |
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