RUSSIAN JOURNAL OF EARTH SCIENCES, VOL. 20, ES5003, doi:10.2205/2020ES000703, 2020

Figure 7. Thin sections and SEM photomicrographs of the studied samples; a–b) The late diagenetic stage of galaxite ($glx$) precipitation indicated with acicular-needle like morphology enclosing the pore spaces; c–d) Romanechite ($Rom$) is seen in the form of vein cross-cutting the ground mass of both cryptomelane ($crypt$) and pyrolusite ($pyr$). Thin films of galaxite ($glx$) are mostly evident in the form of lining around the pore spaces; e) Alteration of pyrolusite phase indicated with a crack like structural pattern and its replacement by romanechite, f) Pseudomorphic replacement replacement of clay mineral smectite and formation of cryptomelane (KMn$_8$O$_{16}$) – view under polarizing microscope; g) Manganese oxides mineral phases in the form of lamina around a nucleus fragment; romanechite and cryptomelane on the outer shell – view under polarizing microscope; h) Late diagenetic stage of mineral precipitation is also characterized by precipitation of thin films of galaxite around the pore-spaces – view under polarizing microscope.

 
Citation: Pharoe Benedick Kinshasa, A. N. Evdokimov, I. M. Gembitskaya, Christopher Baiyegunhi, Zusakhe Nxantsiya (2020), Mineralogy, geochemistry and geological occurrence of supergene manganese ore mineralization in North West Province, South Africa, Russ. J. Earth Sci., 20, ES5003, doi:10.2205/2020ES000703.
 

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