摘要
In Nagpur, M.P.-Maharashtra Manganese Belt is exposed which is part of Sausar Belt. In Nagpur, four manganese mines viz Mansar, Kandri, Beldongri and Satak are selected for the ore microscopic study. These mining areas are situated in that part of Central India which are highly deformed and metamorphosed and are characterised by high grade amphibolite facies to low grade greenschist facies. The Precambrian manganese ore deposits of Nagpur are formed by the metasediments of Sausar belt which is rich in manganese sediments. The manganese ores of the study area are co-folded with distinct rock types i.e. “gondites” and predominantly composed of a mixture of braunite, bixbyite, hausmannite, hollandite, jacobsite, vredenburgite, pyrolusite, cryptomelane and psilomelane. The dominant rocks are tirodi migmatitic gneiss, argillaceous and calcareous rock types. This paper discusses the mineralogy of the manganese ores of Kandri, Mansar, Satak and Beldongri. After the careful assessment of mineralogy, texture and paragenesis of the manganese ore of the study area, it has been concluded that the manganese ores of the study area are formed by the multiple processes i.e. metamorphism and supergene enrichment. These supergene enrichments are evidence of colloidal influx. Occurrence of free braunite, free hausmannite and free jacobsite indicates the high grade metamorphism. Pyrolusite, rhodonite, and psilomelane-cryptomelane are formed by supergene enrichment. The presence of lamellar twinning in braunite indicates about shear pressure. In this area the different manganese mineral assemblages and their textures suggest about the occurrence of different metamorphic activity and depositional environment. The texture and paragenesis of manganese ore of the study area are discussed here.
In Nagpur, M.P.-Maharashtra Manganese Belt is exposed which is part of Sausar Belt. In Nagpur, four manganese mines viz Mansar, Kandri, Beldongri and Satak are selected for the ore microscopic study. These mining areas are situated in that part of Central India which are highly deformed and metamorphosed and are characterised by high grade amphibolite facies to low grade greenschist facies. The Precambrian manganese ore deposits of Nagpur are formed by the metasediments of Sausar belt which is rich in manganese sediments. The manganese ores of the study area are co-folded with distinct rock types i.e. “gondites” and predominantly composed of a mixture of braunite, bixbyite, hausmannite, hollandite, jacobsite, vredenburgite, pyrolusite, cryptomelane and psilomelane. The dominant rocks are tirodi migmatitic gneiss, argillaceous and calcareous rock types. This paper discusses the mineralogy of the manganese ores of Kandri, Mansar, Satak and Beldongri. After the careful assessment of mineralogy, texture and paragenesis of the manganese ore of the study area, it has been concluded that the manganese ores of the study area are formed by the multiple processes i.e. metamorphism and supergene enrichment. These supergene enrichments are evidence of colloidal influx. Occurrence of free braunite, free hausmannite and free jacobsite indicates the high grade metamorphism. Pyrolusite, rhodonite, and psilomelane-cryptomelane are formed by supergene enrichment. The presence of lamellar twinning in braunite indicates about shear pressure. In this area the different manganese mineral assemblages and their textures suggest about the occurrence of different metamorphic activity and depositional environment. The texture and paragenesis of manganese ore of the study area are discussed here.
