TY - JOUR A1 - Reif,J. T1 - Occurrence of manganese carbonates ores on strata-bound Horni Benesov deposite (Silesia, Czech Republic) JF - Bulletin of Geosciences JA - Bull. Geosci. Y1 - 2000 VL - 75 IS - 4 SP - 449 EP - 454 CY - Prague PB - Czech Geological Survey SN - 1803-1943 (online), 1802-6222 (print) AV - Free KW - Sternberk-H. Benesov Belt KW - strata-bound deposite KW - Devonian KW - manganese carbonate and iron oxide ores KW - mineralogy AB - Occurrence of manganese carbonates ores represented by rodochrosite and Fe-rodochrosite with inferior amount of siderite, ferrostilpnomelane, chlorite, limonite, hematite and magnetite was discovered on Horni Benesov sulphides deposit. Lattice parametres of rodochrosite are a = 0.4765(2) nm, c = 1.5674(2) nm and for siderite a = 0.4693(1) nm, c = 1.5462(3) nm. Chemical composition of rodochrosite was as follows: 79.5 % MnCO3, 17,5 % FeCO3, 2.6 % CaCO3, 0.3 % MgCO3. Rodochrosite was observed as relatively small grained or concentric radial agregate. Agregates of rodochrosite represented originally very small grade metamorphosed relicts of volcano-sedimentary ore accumulation. Mn-carbonates ores were probably a primary source of secondary wad and psilomelane accumulations in the supergene zone of Horni Benesov sulphide deposit. The isotopic compositions of C and O of siderite were - 26.6 ‰ delta;13C and 22.9 ‰ delta;18O (average of 2 measurement) and for rodochrosite - 14 ‰ delta;13C and 22.8 ‰ delta;18O. ER -