『Abstract
As a prerequisite for an experimental study of the Mn-Al-Si-O system, the solubility of Al in braunite, partridgeite and hausmannite, as well as Mn³⁺ in galaxite and viridine, was investigated using hydrothermal cold-seal and piston-cylinder apparatus. Equilibrium relations were mainly determined at 600゜C and 4 kbar, with fO2 controlled by the solid buffers Mn2O3/MnO2, Mn3O4/Mn2O3, Cu2O/CuO, Cu/Cu2O, Fe3O4/Fe2O3 and Ni/NiO. the fO2 for the reaction pyrolusite (pyr) + quartz = braunite (brn) + O2 and Al2SiO5 + pyr + qtz = viridine (vir) or kanonaite (kan) lies above the Mn2O3/MnO2 buffer. The reaction brn + qtz + vir = spessartine (sps) takes place at fO2 conditions between the Mn2O3/MnO2 and Mn3O4/Mn2O3 buffers, whereas the reaction brn + vir = sps + corundum (cor) + O2 lies just below the latter. Between the fO2 of the Cu2O/CuO and Cu/Cu2O buffers, the reactions brn + qtz = rhodonite (rdn) + O2, vir = sps + sillimanite (sil) + cor, brn + cor = hausmannite (haus) + sps + O2, brn + rdn = tephroite (teph) + O2, brn = haus + teph + O2, haus + cor = galaxite (gal) + O2 and haus + sps = gal + teph + O2 take place with decreasing O2. At lower total pressure, higher temperature and appropriate fO2, braunite is not stable with tephroite, and will decompose to rhodonite and hausmannite. The resulting isothermal isobaric sections for the different buffers are compared with natural mineral assemblages in aluminous manganese-rich rocks. Most of the variability of mineral assemblages within a manganese deposit and the persistence of certain minerals like braunite, piemontite and viridine from very-low-grade to amphibolite-facies conditions can be explained by the experimentally derived equilibrium reactions. The most critical parameters for these reactions seem to be oxygen fugacity and, to a lesser extent, temperature and total pressure.

Key-words: Mn-Al-Si-O system, hydrothermal experiments, controlled fO2, Mn-silicates, Mn-oxides, metamorphic parageneses.』

Introduction
Experimantal methods
Run conditions
Starting materials: chemicals and minerals
Analytical methods
　Synthetic samples
　 Natural samples
Experimantal results
Syntheses and properties of solid solutions in the Mn-Al-Si-O system
　Partridgeite-corundum solid solutions
　Hausmannite-galaxite solid solutions
　Braunite-“Al-braunite” solid solution
　Al2SiO5-“Mn³⁺2SiO5” solid solutions
Stability rekations in the Mn-Al-Si-O system
　Mn-Al-O system
　Part/Pyr buffer
　Haus/Part buffer
　 Cu2O/CuO buffer
　Mag/Hem buffer
　Mn-Si-O system
　Mn-Al-Si-O system
Aluminous manganese-rich mineral parageneses
Discussion
Acknowledgements
References