resulted in the formation of hematite, goethite, kaolinite and varlamoffite (Antun, 1960). In general, no columbite-tantalite can be found. (Fernandez-Alonso et al., 2012). ... luster can be identified. …
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Disseminated cassiterites are enriched in Ta2O5 and Nb2O5 compared to vein cassiterites. Disseminated columbite-tantalites evolve toward Mn- and Ta-rich chemistries that …
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Download scientific diagram | Unit cell dimensions of columbite-tantalites and wodgin- ites from the Peerless Pegmatite from publication: Wodginite and associated oxide minerals from the …
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Unmixing bodies of tapiolite (Fe, Mn)(Ta,Nb) 2 O 6 occur in some deep-colored cassiterites or in some areas thereof. They can form extremely fine needles, oriented or not. In granites, …
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U–Pb ages of columbite-tantalite samples vary between ∼975 Ma and ∼930 Ma.The oldest ages (975 + 8.2/−8.3 Ma and 966 + 8.7/−8.6 Ma) overlap with previous reported Rb–Sr …
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Columbite-group minerals (CGM: columbite-tantalite solid solution series) account for the majority of the current tantalum production in rare metal-endowed granitic pegmatite. …
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Columbite-tantalite formed during the crystallisation of the pegmatites, followed by intense alkali metasomatism, i.e. widespread growth of albite and white mica. The major part of …
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Three X-ray diffractograms are presented [based on the averages of all diffractograms, and differences in: 1) disordered columbite or tantalite (110 peak may or may not be present, but when it is ...
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Etude tectono-métamorphique, magmatique et minéralisations de columbite-tantalite et de cassitérite de la chaîne Karagwe-Ankole (KAB). Cas de la région de Kabarore-Mparamirundi …
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Mineralogy and chemistry of columbite-tantalite from Bugarura-Kuluti area, Karagwe-Ankole Belt, Rwanda: Indicators of pegmatite and granite evolution ... (Fe) inclusions …
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Columbite-group minerals (CGM: columbite-tantalite solid solution series) account for the majority of the current tantalum production in rare metal-endowed granitic pegmatite. …
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Ryznar J, Prsek J, Włodek A, Uher P (2023) Mineralogy and chemistry of columbite-tantalite from Bugarura-Kuluti area, Karagwe-Ankole Belt, Rwanda: indicators of …
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For instance, tin, tantalite, columbite, zircon, ilmenite, and wolframite are buried in the bowels of Plateau, Nasarawa, Kaduna State, etc. This research aims at discussing the importance of cassiterite mining in Plateau …
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The age of apatite, cassiterite, columbite-tantalite (coltan) from five zones in Nanping No.31Li–Cs–Ta-rich type pegmatite deposit show remarkable two group ages …
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Columbite-tantalite crystals occur within quartz and albite, or are semi-enclosed by quartz and lepidolite in the late-stage mineralized granite without alteration (Fig. 2 D, E) and no veinlet …
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Mineralogical analysis reveals that anomalous Sn and Ta in these stream sediments can be attributed to the presence of columbite-tantalite, tapiolite, microlite, and …
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Late Neoproterozoic over of the cassiterite and columbite-tantalite bearing pegmatites of the Gatumba area, Rwanda (Central Africa) J. Afr. Earth Sci. ... The exogranitic …
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Tantalite-columbite and tantalian rutile occur in cassitertie with exsolution texture and/or infiltrate into the micro-fissures of cassiterite with micro quartz vein. The compositions of tantalite …
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Dissolution textures resulting from the corrosion of columbite and tantalite rims, in particular, are common. The Mn/(Mn + Fe) ratio varies between 0.33 and 0.97 and the Ta/(Ta …
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Tantalite ≤86% Ta 2 O 5 and Columbite ≤78% Nb 2 O 5 Orthorhombic stunted tabular or slender striated, radiating crystals Opaque, black to grey to brown, sub-metallic to -resinous lustre and …
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The pegmatites of the Gatumba area (western Rwanda) have historically been mined for their columbite-tantalite and cassiterite mineralisation, but contain also beryl, apatite, spodumene, …
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The compositional variations of columbite-tantalite (in terms of Ta/(Ta + Nb) and Mn/(Mn + Fe) ratios) and zircon (in terms of Hf contents) from different pegmatites correlate with the degree …
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Clear yellowish or honey-colored cassiterites are classed as gemstones. Iron, Mn, Ta and Nb can substitute for Sn with a combination of divalent and pentavalent elements replacing the …
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Accessory minerals, including zircon, thorite, monazite, columbite-tantalite, cassiterite, bastnaesite, and xenotime are present in all phases of the Madeira igneous complex, indicating the ...
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This is supported by studies showing that the sediments in catchments with lithium pegmatites contain the tin and tantalum ore minerals cassiterite and columbite-tantalite, respectively,...
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type I cassiterites are from pegmatites (cf . Deer et al., 1962) and they are often associated with (and mistaken for) columbite and tantalite. Cassiterites of type II (Plates Ia,b,c)1 contain …
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Cassiterites of different origins. ... Generally, Nb, Ta, and Ti are separated from the matrix of columbite-tantalite by acid hydrolysis or tannic acid precipi- tation. The separated fraction is ...
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The pegmatites are associated with both the columbite–tantalite (coltan) and cassiterite mineralisation in the KAB. The columbite-tantalite mineralisation in the Gatumba …
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Cassiterite, tantalite, columbite and tantalian rutile are found as accessory minerals in Soonkyoung tin-bearing pegmatites. These minerals occur as finely disseminated specks of up …
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cassiterites from epithermal and mesothermal veins. The crystal habit is bipyramidal with the common {111} form, and a small development along the c axis is common in cassiterites from …
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