Formation of high-grade manganese ores in the Kalahari manganese field, South Africa: evidence from fluid inclusion studies in co-genetic iron and manganese oxides, and gangue minerals

摘要

Fluid inclusions in hematite and hausmannite from high-grade Wessels-type ore from the Kalahari Manganese Field were studied using infrared microscopy. The data obtained suggest that both minerals deposited co-genetically along with gangue minerals such as calcite and datolite from high-salinity fluids. The minerals constituting the high-grade manganese ore were deposited at temperatures below 200 deg, well below the temperature range of 200-400 deg that was estimated on the basis of the thermodynamic stability of observed mineral assemblages.