Columbite-Tantalite Distribution and Placer Formation in Humid Tropical Areas: Taking Issia Columbite-Tantalite District, Central Western Ivory Coast as an Example

详细信息   

• 责任者：Benjamin A. Allou (Centre d’études sur les Ressources Minérales ; Université du Québec à Chicoutimi ; 555 Bd de l’Université ; Chicoutimi ; Quebec ; Canada ; G7 H 2B1) ; Lu Huanzhang
• 刊名：Geotectonica et Metallogenia
• 出版年：2008
• 卷期：32(2)
• 关键词：铌矿 ; niobium ores ; 钽矿 ; tantalum ores ; 砂岩矿床 ; sandstone deposits ; 科特迪瓦 ; Cote Divoire
• 页码：p.195-211
• 图表：12 illus., 4 tables, 49 refs.
• 分类号：1001
• issnNo：ISSN1001-1552
• isbnNo：CN43-1595/P

摘要

The Etienne-Meguhe and Bemadi mines are the major columbite-tantalite deposits of the Issia district, Central Western Ivory Coast. They are different in geomorphology, style of mineralization and geological evolution. The Etienne-Meguhe deposit, located on a large interfluve, is an eluvial deposit resulting from kaolinization which produced a significant volume reduction and the subsequent concentration of chemically stable minerals, such as quartz, and niobium-tantalum and beryllium bearing minerals. The Bemadi deposit is an ideal placer resulting from river transport which caused fragmentation, rounding, and finally accumulation of dense minerals along natural traps. Under these conditions, the columbite-tantalite grains do however become more and more rounded and their size decreases gradually without any chemical changes. Thus, under atmospheric conditions in the humid tropical areas, even if the chemical properties of this mineral are preserved, the physical properties change gradually from the eluvial zones to the alluvial zones.