Supergene manganese ore records 75 Myr-long Campanian to Pleistocene geodynamic evolution and weathering history of the Central African Great Lakes Region – Tectonics drives, climate assists

Abstract

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Influence of Genetic Processes on Geochemistry of Fe-oxy-hydroxides in Supergene Zn Non-Sulfide Deposits

“…Typical supergene minerals, like hemimorphite, cerussite, anglesite, smithsonite, hydrozincite and Fe-oxy-hydroxides, have overprinted both the sulfide and the willemite mineralization, following different weathering stages likely started in Late Cretaceous-Early Eocene, and lasted until Mio-Pliocene. The climatic conditions and ages are in agreement with the weathering processes which were associated with supergene manganese ores in the Central African Great Lakes region (Democratic Republic of Congo), where the supergene assemblages record weathering stages likely started during relatively cold Late Mesozoic and Paleogene periods (likely Campanian) and ongoing until the more recent humid/warm Neogene [57]. Fe-oxy-hydroxides at Kabwe consist of both goethite and hematite.…”

Multistage genesis of the late Cretaceous manganese karst-hosted Tasdremt deposit (High Atlas, Morocco)

“…This set of analysis contrasts with the analyses of K-Mn oxides that crystallize in a strictly supergene domain as observed in lateritic weathering profiles (e.g., Hénocque et al 1998;Colin et al 2005;Beauvais et al 2008;De Putter et al 2015;De Putter and Ruffet 2020). At surface pressure and temperature, K-Mn oxides are stable, which does not facilitate a substantial remobilization of Mn.…”

“…Plateau and pseudo-plateau ages assumed to be valid are shown in bold. Degassing spectra (16AOU10 and 16AOU17 in 9b) and resizing of age spectra (density probability diagram in 9d) after De Putter et al (2015) and De Putter and Ruffet (2020). Apparent age error bars are at the 1σ level; errors in the J-parameter are not included.…”

Differentiated Neogene bauxitization of volcanic rocks (western Cameroon): Morpho-geological constraints on chemical erosion

“…59 to ca. 45 Ma (Beauvais et al, 2008) upon the African surface that extends from West to East and South-East Africa (Beauvais and Chardon, 2013;Burke and Gunnell, 2008;see also Pérello et al, 2020;De Putter and Ruffet, 2020). Likewise, thick bauxitic profiles later formed from weathering of 14 Ma to 23 Ma old trachyte and basalt are well preserved at altitudes of 1500 to 1800 m in the eastern Nigeria (Schwarz, 1997).…”

“…Likewise, thick bauxitic profiles later formed from weathering of 14 Ma to 23 Ma old trachyte and basalt are well preserved at altitudes of 1500 to 1800 m in the eastern Nigeria (Schwarz, 1997). With the mid-Miocene climatic optimum, Lateritic weathering intensified in Africa (e.g., Beauvais et al, 2008;De Putter and Ruffet, 2020), and more generally on continents of the inter-tropical belt (Retallack, 2010) even at relatively high altitudes, e.g., upon elevated continental margins (Jean et al, 2020), where transported-limited erosion regimes have potentially controlled landscapes evolution over the Cenozoic.…”