 | | Journal (article/letter/editorial) | | tourmalinites of the Duruchaus Formation of central Namibia reveal a common compositional trend that occurs...this trend Fe3þ along a join between ‘‘oxy-dravite’’ [Na(Mg2Al)(Al6)(Si6O18)(BO3)3(OH)3(O)] and povondraite...more magnesian and fall close to the dravite and ‘‘oxy-dravite’’ compositions. These latter tourmaline...tourmaline, mineral chemistry, tourmalinites, Namibia, evaporite, magnesian. Introduction The pioneering...Formation of the Damara Orogenic Belt in central Namibia are of special interest because they contain well-preserved |  | | Journal (article/letter/editorial) | | Upper Proterozoic Damara Orogen, South West Africa/Namibia. Two genetically different fluid systems of regional...thick geosynclinal sequences of the Damara Trough (Khomas Group). Further fluid systems of local importance...Hakos/Dordabis j,..,, i;l I 282& I 2016~28 Khomas ' Trough ~ o .~, +~o ,~ +2s .~c CO Fig...metapelites and metapsammites with low-saline fluids (Khomas Trough). PLATE I Solid phases in fluid inclusions...(photo, D. Hallbauer). d. Metaplaya occurrence, Gurumanas. Fluid inclusion in albite pseudomorph after thenardite |  | | Journal (article/letter/editorial) | | Fe 3+ and WO, and follow a trend between “oxy-dravite” and povondraite (O–P trend). This compositional...(X) (Y3) Alkali group Schorl Oxy-schorl Dravite “Oxy-dravite”a Povondraite Na Na Na Na Na X-site vacant... The tourmaline species generated are dravite and “oxy-dravite” at high Na (and Cl) in the fluids and...Paleozoic sedimentary rocks from the Appalachian region (Henry et al., 1994; Krynine, 1946) and Switzerland...were considered to be elbaite, dravite, schorl, uvite and chromium dravite (e.g. Krynine, 1946; Srivastava |  | | Journal (article/letter/editorial) | | where R is predominantly Fe 2+ in schorl, Mg in dravite, and (A1 + Li) in elbaite. Na may be partially...massive-sulfide tourmalines fall mainly within the schorl-dravite solid solution series, with a tendency for Mg-rich...have compositions intermediate between schorl and dravite (Ethier and Campbell 1977; Appel and Garde 1987;...South Africa Cu, Zn Gorob prospect, Namibia None Onguati area, Namibia Cu Kilembe mine, Uganda Pb, Zn, Ag...Farm Gurumanas, Namibia Farm Gurumanas, Namibia Farm Stolzenfeld, Namibia Ondundu area, Namibia Gouverneur |  | | Book | | Spitzkoppe, Erongo 9 , .,/, loringa tree . Khomas Highland with Gamsberg 11 lnselberge, Helmeringhausen...Mountainland The Central Northern to Northwest Region including Damaraland The Central Namib Desertand...Copper Deposits The South The Pegmatitesin Central Namibia Luderitz and the Diamonds 44 49 241 254 272 275... Encyclopedia of the Mineralsof Namibia 443 Meteorites in Namibia Bibliography Index Photo credits...__ Republic of Namibia The President State House W°Ntdhoek FOREWORD Namibia is endowed with an |  | | Journal (article/letter/editorial) | | Eu/Eu* ¼ 058 6 003). Tourmaline is dravite and/or ‘oxy-dravite’ with a tendency to povondraite, showing...(Fig. 9c). The data plot parallel to the ‘oxy-dravite–povondraite’ join and therefore the FeAl–1/AlO[R(OH)]–1...FeAl–1/AlO[R(OH)]–1 exchange, but with a tendency to dravite (Fig. 9d). For the large tourmaline shown in Fig...2.0 AlO(Fe(OH))–1 1.5 1.0 0.5 0.0 3.5 „oxy-dravite“ 4.0 4.5 Al (N 6.3 rim I aM rim II g)...9 3.0 5.5 AI-2 AI-3 FeAl–1 2.5 6.5 6.0 Dravite 6.5 7.0 5.0 2.3 2.4 2.5 2.6 2.7 Na + Mg |
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