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SEM-Based Automated Mineralogy – Micrometric mapping to trace the origins and refine the diagenetic evolution of the ultrafine-grained mangano-lutite of the Kalahari Manganese Deposit, South Africa.

The Kalahari Manganese Field (KMF) of the Northern Cape Province of South Africa hosts about 74% of all known minable manganese ores globally. It represents the largest known land-based Mn deposit. More than 90% of the resource can be best described as mangano-lutite, e.g., a microcrystalline, ovoid-rich, finely laminated chemo-sedimentary rock containing between 30-40 wt.% Mn. Despite its great geological age (2.42 Ga), the mangano-lutite and its surrounding volcano-sedimentary host rock succession (Transvaal Supergroup) have not experienced any significant metamorphic overprint. Owing to its exceptionally fine-grain size and unusual composition, the mineral paragenesis and diagenetic microfabric of the mangano-lutites remain poorly documented. This contribution aims to show that modern SEM-EDS-based image analysis platforms, such as the TESCAN TIMA instrument, can not only provide quantitative mineralogical data, but can also reveal unprecedented insight into diagenetic microfabric and a complex succession of mineral assemblages in the mangano-lutites. The instrumental approach developed for this application is of extreme industrial and economic importance due to increasingly complex ores and a mandatory need to beneficiate by-products in the shift to sustainable mining. It can be easily transferred to other applications on fine-grained rocks (e.g. carbonate mudstones, fault gouges), ores (e.g. nickel laterites, bauxites) or anthropogenic solid materials (e.g. tailings, flue dusts).

Details

Author
Valentin OGÉ1, Bradley Martin GUY1, Jens GUTZMER2
Institutionen
1Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Freiberg, Germany; 2Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Freiberg, Germany;Paleoproterozoic Mineralization (PPM) Research Group, Department of Geology, University of Johannesburg, Johannesburg, South Africa
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/a14r-h074
Geolocation
South-Africa