MANGANEM BOHATÉ POVLAKY NA STĚNÁCH CÍSAŘSKÉ JESKYNĚ (MORAVSKÝ KRAS)
Roč.7,(2000)
Abstrakt
Klíčová slova:
Eh-pH diagram; limestone; dissolution; precipitation; manganese oxy-hydroxide
Abstract: The dark coatings and crusts on the walls of the Císařská cave (the Moravian Karst) were studied. Some of them contain the increased amounts of manganese, up to 7 wt. % of MnO. Based on SEM and EDXR analyses, phases with 27 to 50 wt. % of MnO were identified. By X-ray diffraction, however, any regular Mn-minerals were not found. The cave fresh water (t = 8°C, Eh = 0.474V, pH = 7.02, aMn2+ = 0,045 ppm Mn) was unsaturated to Mn-minerals. Some of the dripping waters (t = 8°C, Eh ~ 0.478 to 0.514 V, pH ~ 7.9 to 8.05, aMn2+ ~ 0.001 to 0.009 ppm Mn) approached the equilibrium with pyrolusite and manganite. The sources of manganese and the mechanisms of transport are discussed.
Eh-pH diagram; limestone; dissolution; precipitation; manganese oxy-hydroxide
Reference
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