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First Report of Cryptomelane in Altered Rhyolite from Tazrouk Volcanic District, Latea, Hoggar, Algeria

  • Riad Ben El KhaznadjiEmail author
  • Abderrahmane Bendaoud
  • Abderaouf Seffari
Chapter
Part of the Advances in Science, Technology & Innovation book series (ASTI)

Abstract

X-ray diffraction, ore microscopy, and electron microprobe studies have been implemented on ore samples obtained from rhyolitic rock collected at the Tazrouk volcanic district, Hoggar. The identified manganese ore minerals include Alkali-felspar, Magnesio-arfevdsonite and cryptomelane. All these minerals are poorly crystalline. The minerals’ chemical compositions indicate little contamination with other elements. Modes of occurrence are principally taking place through replacements, cavity or fracture fills, leaching and precipitation. Mineral associations seem rather complex, which makes definite paragenetic relations impossible to establish. Supergene formation of the manganese oxide ore is highlighted by the abundance of manganese minerals in solution channels, such as fractures and cavities within silicate gangue. Much of the ore, however, appears to have been enriched by leaching of gangue minerals and the subsequent addition of manganese. Noteworthy, also, is that this large field occurrence of cryptomelane has initially been described with respect to the Hoggar shield.

Keywords

Cryptomelane Manganese ore Rhyolite Tazrouk Mineralisation Hoggar 

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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Riad Ben El Khaznadji
    • 1
    Email author
  • Abderrahmane Bendaoud
    • 2
  • Abderaouf Seffari
    • 2
  1. 1.Laboratoire de Métallogénie et Magmatisme de l’AlgérieUSTHBBab EzzouarAlgeria
  2. 2.Laboratoire de Géodynamique, Géologie de l’Ingénieur et PlanétologieUSTHBBab EzzouarAlgeria

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