Abstract
In the metamorphosed manganese oxide ores of India, braunite is ubiquitous in all assemblages from chlorite to sillimanite grades. Chemical analyses of braunite from different prograde assemblages confirm the presence of a fixed R2+ (=Mn2++Mg+Ca) SiO3 molecule in the mineral. Element partitioning between coexisting braunite and bixbyite indicates a near-ideal mixing of Fe+3/ -Mn+3 in the phases. This also indicates that braunite became relatively ferrian while equilibrating with associated phases such as bixbyite, hollandite and jacobsite during prograde reactions. Petrogenetic studies show that as a general trend, prograde lower oxide phases appeared by deoxidation of higher oxide phases. But braunite, a more reduced phase than bixbyite, appeared early from deoxidation of pyrolusite in presence of quartz. Bixbyite could appear later from the reacting pyrolusite-braunite-quartz assemblage. Inferred mineral reaction paths and the general trend of pro-grade deoxidation reactions suggest that the composition of ambient fluid phase was internally buffered during metamorphism.
Similar content being viewed by others
References
Abraham K, Schreyer W (1975) Minerals of the viridine hornfels from Darmstadt, Germany. Contrib Mineral Petrol 49:1–20
Abs-Wurmbach I (1980) Miscibility and compatibility of braunite, Mn2+ Mn 3+6 O18/SiO4 in the system Mn-Si-O at 1 atm. in air. Contrib Mineral Petrol 71:393–399
Abs-Wurmbach I, Langer K (1975) Synthetic Mn3+ kyanite and viridine (Al2−xMn3+)SiO5 in the system Al2O3-MnO-MnO2 -SiO2. Contrib Mineral Petrol 49:21–38
Abs-Wurmbach I, Peters TJ, Langer K, Schreyer W (1983) Phase relations in the system Mn-Si-O: an experimental and petrological study. N Jahrb Mineral Abh 146:258–279
Bence A, Albee A (1968) Empirical correction factors for the electron microanalysis of silicates and oxides. J Geol 76:382–403
Bhattacharyya PK, Dasgupta S, Fukuoka M, Hirowatari F, Roy S (in press): Mineralogy and mineral chemistry of metamorphosed manganese oxide ores and manganese silicate-oxide rocks — the example from the Precambrian Sausar Group, In dia. Volume of Leading Papers, 27th I.G.C., Moscow, 1984
Burns RG, Burns VM (1977) Mineralogy. In: Marine Manganese Deposits, Glasby GP (ed) Elsevier, Amsterdam, pp 185–248
Dasgupta HC, Manickavasagam RM (1981a) Regional metamorphism of non-calcareous manganiferous sediments from India and the related petrogenetic grid for a part of the system Mn-Fe-Si-O. J Petrol 22:363–396
Dasgupta HC, Manickavasagam RM (1981b) Chemical and X-ray investigation of braunite from the metamorphosed manganiferous sediments of India. N Jahrb Mineral Abh 142:149–160
De Villiers JE (1945) Some minerals occurring in South African manganese deposits. Trans Geol Soc S Africa 48:17–26
De Villiers JA (1951) The manganese ores of Otjosondu, South West Africa. Trans Geol Soc S Africa 54:89–98
De Villiers PR, Herbstein FH (1967) Distinction between two members of the braunite group. Am Mineral 52:20–30
De Villiers PR (1975) The crystal structure of braunite with reference to its solid solution behaviour. Am Mineral 60:1098–1104
Fleischer M (1964) Manganese oxide minerals. VIII Hollandite. In: Advancing Frontiers in Geology and Geophysics, Subramanian AP, Balakrishna S (eds). Indian Geophys Union, Hyderabad, pp 176–187
Hino H, Minato T, Kushakaba Y (1978) Hydrothermal synthesis of braunite in the systems manganite (MnOOH) — silica (SiO2), hausmannite (Mn3O4) — silica (SiO2) and pyrolusite (MnO2) — silica (SiO2) (2,500 bars). Mem Fac Eng Kyoto Univ 40:16–29
Huebner JS (1967) Stability relations of minerals in the system Mn-Si-C-O. Ph D Thesis. The Johns Hopkins University, Baltimore, USA, pp 279
Huebner S (1969) Stability relations of rhodochrosite in the system manganese-carbon-oxygen. Am Mineral 54:457–481
Huebner JS, Sato M (1970) The oxygen fugacity-temperature relationships of manganese oxide and nickel oxide buffers. Am Mineral 55:934–952
Mason B (1943) Mineralogical aspects of the system FeO-Fe2O3-MnO-Mn2O3. Geol Fören Stockholm Förhandl 65:97–190
Mason B (1944) The system Fe2O3-Mn2O3: some comments on the names bixbyite, sitaparite and partridgeite. Am Mineral 29:66–69
Moore PB, Araki T (1976) Braunite: its structure and relationship to bixbyite and some insights on the genealogy of fluorite derivative structures. Am Mineral 61:1226–1240
Muan A (1959a) Phase equilibria in the system Manganese Oxide -SiO2 in air. Am J Sci 257:297–315
Muan A (1959b) Stability relations among some manganese minerals. Am Mineral 44:946–960
Ostwald J (1982) Some observations on the mineralogy and genesis of braunite. Mineral Mag 46:506–507
Peters TJ, Valarelli JV, Candia MAF (1974) Petrogenetic grids from experimental data in the system Mn-Si-C-O-H. Revta Bras Geociencias 4:15–27
Peters TJ, Valarelli JV, Coutinho JMV, Sommerauer J, Von Raumer J (1977) The manganese deposits of Buritirama (Para, Brazil). Schweiz Mineral Petrogr Mitt 57:313–327
Roy S (1962) Study of the metamorphic manganese ores of Bharweli Mine-area, Madhya Pradesh, India and their genesis. Econ Geol 57:195–208
Roy S (1966) Syngenetic Manganese Formations of India. Jadavpur University, Calcutta, pp 219
Roy S (1980) Manganese ore deposits of India. In: Geology and Geochemistry of Manganese. Varentsov IM, Grasselly G (eds) vol. 2; 237–264. Adkademiai Kiado, Budapest
Roy S (1981) Manganese Deposits. Academic Press, London, pp 458
Roy S, Bandyopadhyay PC, Bose PK (1982) Geology and genesis of the manganese deposits of the Penganga Beds, Adilabad District, Andhra Pradesh, India. VI IAGOD Symposium, Tbilisi, Collected Abstracts: 305–306
Stanaway KJ, Kobe HW, Sekula J (1978) Manganese deposits and the associated rocks of Northland and Auckland, New Zealand. NZ Journ Geol Geophys 21:21–32
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bhattacharyya, P.K., Dasgupta, S., Fukuoka, M. et al. Geochemistry of braunite and associated phases in metamorphosed non-calcareous manganese ores of India. Contr. Mineral. and Petrol. 87, 65–71 (1984). https://doi.org/10.1007/BF00371403
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00371403