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DOI | 10.25131/gssajg.120.1.77 |
Tantalum-(niobium-tin) mineralisation in pegmatites and rare-metal granites of Africa | |
Melcher, F.1; Graupner, T.2; Oberthuer, T.2; Schuette, P.2 | |
通讯作者 | Melcher, F. |
会议名称 | 35th International Geological Congress (IGC) |
会议日期 | AUG 27-SEP 04, 2016 |
会议地点 | Cape Town, SOUTH AFRICA |
英文摘要 | Tantalum is an important metal for high-technology applications of the modern world. It is recovered from oxide minerals that are present as minor constituents in rare-metal granites (RMG) and granitic rare-element pegmatites (REP). Significant potential exists as a by-product of spodumene mining from pegmatites, and from Nb-Zr-rare earth element (REE) mining from carbonatites and peralkaline igneous rocks. Columbite-group minerals (CGM) account for the majority of the current Ta production; other Ta-Nb oxides such as tapiolite, wodginite, ixiolite, rutile and pyrochlore-supergroup minerals are of minor importance. The estimated Ta resources of Africa are >50,000 tons of contained Ta2O5, representing 16% of the world resources. Currently, the economically most important mining districts in Africa are located within the Kibara Belt (mainly Rwanda and the DR Congo), around the Kenticha mine (Ethiopia) and in the Alto Ligonha Province (Mozambique). Production from pegmatites and related placer deposits is mostly from hundreds of artisanal and small-scale workings with only a handful of semi -industrial Ta mines. Collectively, African operations are currently responsible for more than half of the world's primary Ta. Rare -metal granite and REP districts in Africa are part of Archaean, Palaeoproterozoic, Neoproterozoic, Palaeozoic and Mesozoic provinces. Each period of Ta ore formation is characterised by specific mineralogical and geochemical features. Compositions of CGM are variable: Fe-rich types predominate in the Man Shield (Sierra Leone), the Congo Craton (DR Congo), the Kamativi Belt (Zimbabwe) and the Jos Plateau (Nigeria); Mn-rich columbite-tantalite is typical of the Alto Ligonha Province (Mozambique), the Arabian-Nubian Shield (Egypt, Ethiopia) and the Tantalite Valley pegmatites (southern Namibia) and Large compositional variations through Fe-Mn fractionation, followed by Nb-Ta fractionation are typical for pegmatites of the Kibara Belt of Central Africa, pegmatites associated with the Older Granites of Nigeria and many pegmatites in the Damara Belt of Namibia. Trace element concentrations in CGM and other Ta-Nb oxides are highly variable, with Ti, W, Sn, Zr, Hf, Y, Sc and REE displaying significant regional differences that may be used to discriminate Ta provinces. |
来源出版物 | SOUTH AFRICAN JOURNAL OF GEOLOGY |
ISSN | 1012-0750 |
EISSN | 1996-8590 |
出版年 | 2017 |
卷号 | 120 |
期号 | 1 |
页码 | 77-100 |
出版者 | GEOLOGICAL SOC SOUTH AFRICA |
类型 | Article;Proceedings Paper |
语种 | 英语 |
国家 | Austria;Germany |
收录类别 | SCI-E ; CPCI-S |
WOS记录号 | WOS:000424072200006 |
WOS关键词 | EASTERN DESERT ; TECTONIC EVOLUTION ; FOORDITE-THOREAULITE ; BEARING PEGMATITES ; ELEMENT PEGMATITE ; TA MINERALIZATION ; ZIMBABWE CRATON ; CENTRAL NIGERIA ; GATUMBA AREA ; KIBARA BELT |
WOS类目 | Geology |
WOS研究方向 | Geology |
资源类型 | 会议论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/306139 |
作者单位 | 1.Univ Leoben, Chair Geol & Econ Geol, Peter Tunnerstr 5, A-8700 Leoben, Austria; 2.Fed Inst Geosci & Nat Resources, Stilleweg 2, D-30655 Hannover, Germany |
推荐引用方式 GB/T 7714 | Melcher, F.,Graupner, T.,Oberthuer, T.,et al. Tantalum-(niobium-tin) mineralisation in pegmatites and rare-metal granites of Africa[C]:GEOLOGICAL SOC SOUTH AFRICA,2017:77-100. |
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