Northern South Africa’s Kalahari Manganese Field is the largest terrestrial manganese deposit on Earth.  Intervals of sedimentary manganese-oxide rocks are interbedded with iron-formation and other lithologies in the Hotazel Formation (middle Paleoproterozoic, ~2.05 b.y.).  Specific minerals in the manganese ores vary, but include Mn-oxides, MnFe-oxides, KMn-oxides, CaMn-oxides, and Mn-silico-oxides.  The geologic origin of sedimentary Mn ores in the Kalahari Manganese Field is complex, but includes multiple diagenetic, metamorphic, and other alteration events.


Manganese ore (3.5 cm across) - brownish-black, laminated, sedimentary manganese-oxide rock from the Hotazel Formation (uppermost Transvaal Group, middle Paleoproterozoic, ~2.05 b.y.) at the N’Chwaning II Mine in the Kalahari Manganese Field, Northern Cape Province, northern South Africa.




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