The abundance, distribution trends and significance of the major oxides in the host rocks in Vizianagarm Manganese Ores Belt (A.P.) (between N latitude 18˚12' and 18˚30' and E longitudes 83˚20' and 83˚45'), 15 samples of host rocks from different localities of the area under study were collected and analyzed for major oxides. We describe here in major oxides geochemistry of host rocks and manganese ore deposits associated with

A comprehensive study of the manganese ore deposits of Banswara manganese belt (23°10'-23°20'N to 74°15'-74°25'E) in the Banswara district, Rajasthan, has shown a characteristic assemblage of manganese ore minerals. The manganese ore deposits are associated with Aravali phyllite, schist, quartzite and limestone, etc., and occur within a narrow linear belt trending NW-SE. These meta-sediments hosted manganese ores that belong to the Aravalli Supergroup are of Paleo-Proterozoic age. The mineralogical investigation of a number of polished blocks showed the dominance of braunite accompanied by pyrolusite and cryptomelane. A number of mineral assemblages are recommended. The significant ore textures are, banding, replacement and colloform, while other textures identified are veined, granular, brecciated, relict, open space, and mutual boundary relationship. The micro-structural and textural relations are discussed and interpreted to disclose the paragenetic history of ore minerals crystallization, which are usually divided into primary (metamorphic) and secondary (supergene) ores. The aim of this study is to determine the presence of manganese oxides/silicates ore minerals, and to comprehend the sequence of their crystallization. This study is further correlated to a geochemical background of these Mn ores to depict the mode of their origin and depositional settings. The present study has come to the conclusion that the dominance of braunite, banded texture and conformable relations with the associated rocks, indicates the original deposition of syngenetic manganiferous pelitic-psammitic sediments, which, were regionally metamorphosed to form a low grade primary ore deposits but the dominance of pyrolusite, and cryptomelane, along with other secondary manganese ore minerals also pointed out a subsequent chemical weathering and leaching of these earlier formed primary ore, and silicate minerals, resulting in precipitation, and deposition of high grade secondary ore deposits of later origin.

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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 this paper, we described the petrographical characters of the Mn-bearing rock types outcropping in the Kalakhuta, Ghatia, Gararia, Itala, Wagaicha, Tambesara and Talwara villages of Banswara district. The Mn associated rocks in the study area are phyllite, schist, quartzite and limestone. The mineral assemblage in phyllite formed under greenschist facies metamorphism. Petrographic studies of various phyllite samples also reveal that porphyroblasts of biotite sat in the fine-grained micaceous matrix (Biotite, muscovite, chlorite) along with quartz, opaque and ore minerals. Petrographic studies of schist reveal its formation under prograde metamorphism. Mineral assemblages observed in schist are typical of greenschist to lower amphibolite facies. The various schist samples at places show clusters made up of perfect rhombshaped garnets which suggest the increase in the grade of metamorphism. The quartzites are disposed conformably with the phyllites, and are at times brecciated and re-cemented by secondary chert and manganese. These Mn-bearing quartzites are with sutured/serrated and straight grain boundaries. The quartzite samples are fully composed of quartz showing undulose extinction with subordinate feldspar, micas and carbonatic materials. The petrographic characteristics explain that mostly limestones are the dolomitic composition but some ferruginous varieties are also noticed at places. The purer variety of limestone consists of calcite, dolomite and some magnetite but tremolite, quartz and some minute flakes of biotite also occur in impure variety.