Evolution and genesis of fluorite mineralization in the Ouenza region (North-east of Algeria): evidence from fluid inclusions and stable isotopes (C, O, and S)


Bakelli A., Sami L., Boutaleb A., Kolli O., Haddouche O., DEMİR Y. , ...More

ARABIAN JOURNAL OF GEOSCIENCES, vol.15, no.6, 2022 (Journal Indexed in SCI) identifier

  • Publication Type: Article / Article
  • Volume: 15 Issue: 6
  • Publication Date: 2022
  • Doi Number: 10.1007/s12517-022-09726-8
  • Title of Journal : ARABIAN JOURNAL OF GEOSCIENCES
  • Keywords: Tebessa, Ouenza, Fluorite, Fluid inclusions, Raman, Cryo-Raman, MVT, EASTERN MAGHREB, CARBON ISOTOPES, OXYGEN ISOTOPES, RAMAN-SPECTRA, ORIGIN, DEPOSITS, ORE, GEOCHEMISTRY, TUNISIA, BRINES

Abstract

The Ouenza region represents the most important zone for Fe-Pb-Zn (Ba, F, Cu) mineralization in Algeria. The hematitezed iron (siderite) mineralization is mostly controlled by diapiric structures hosted in carbonate sedimentary rocks of the Lower Cretaceous. Polymetallic mineralization (Pb-Zn-Ba, F, Cu) is mainly in epigenetic vein fillings and fractures. Most of the ore bodies are structurally controlled by NE-SW-trending faults. The study of fluid inclusions using Raman and cryo-Raman data in the fluorite and quartz associated with the mineralization confirms the existence of CO2 in the inclusions. The presence of CO2 associated with CH4 and graphite trapped in the fluid inclusions of the fluorite deposited suggest an epigenetic origin for these mineral deposits and allows to characterize the fluid responsible for the fluorite and other associated mineralization deposits. The methods used in this study, including micrometry, Raman, cryo-Raman, and crush leaching, and stable isotopes of sulfur, carbon, and oxygen, suggest an epigenetic origin for these mineral deposits allow the characterization of the fluid responsible for the fluorite deposits and other associated mineralization. The presence of graphite entrapped in the fluid inclusions of the fluorite deposits results from diapiric upward from the basement. Two stages of fluids were examined: (1) an SiO2-rich fluid deposited black quartz crystals with solid inclusions of calcite (H2O-NaCl-CaCl2 system) and CO2 in the vapor phase and (2) a second fluid flowed to depth, recharged with fluorite, sulfide, and sulfate deposited quartz, fluorite, barite, and galena. The crush leaching study in the barite, fluorite, and siderite samples shows lower values of Cl/Br. These results suggest that halite dissolution compared to the Cl/Br ratio varies between 1330 and 9641. The stable isotope results of calcite associated with fluorite and galena mineralization are between 2.6 and - 1.0 parts per thousand for delta C-13(PDB) and between 17.0 and 25.5 parts per thousand for delta O-18(SMOW). The values obtained for delta S-34(CDT) in barite range from + 20.8 to + 23.2 parts per thousand. The combined results suggest that fluids responsible for mineralization are related to basin fluids (formation water) similar to those usually reported for Mississippi Valley (MVT) deposits.