岡山大学 地球科学研究報告
Published by Okayama University Earth Science Reports Editorial Committee

Occurrence and composition of manganese oxide minerals from the Nauta manganese deposit, Western Ghana

Frank k, Nyame Department of Earth Sciences, Faculty of Science Okyamaa University
加瀬 克雄 Department of Earth Sciences, Faculty of Science Okyamaa University
山本 雅弘 Department of Earth Sciences, Faculty of Science Okyamaa University
抄録
X-ray diffraction, ore microscopy, and electron microprobe studies have been done on ore samples obtained from the mine site at Nsuta, Ghana. Manganese ore minerals identified include nsutite, cryptomelane, pyrolusite, and lithiophorite. Except for pyrolusite, all these minerals are poorly crystalline. Chemical compositions of the minerals indicate little contamination by other elements. Quartz, muscovite, and clay minerals feature prominently as gangue in most samples. Textures are varied, and modes of occurrence are prinicipally by replacements, cavity or fracture fills, leaching and precipitaion. Mineral associations seem rather complex, as a result of which definitive paragenetic relations could not be established. Supergene formation of the manganese oxide ore is shown by the abundance of manganese minerals in solution channels such as fractures and cavities within silicate gangue. Much of the ore, howver, appears to have been enriched by leaching of gangue minerals and the later addution of manganese.
キーワード
Nsuta
nsutite
cryptomelane
pyrolusite
lithiophorite
ISSN
1340-7414
NCID
AN10506284