Sedimentology, Metallographic Characteristics and Geodynamic Evolution of the Merija Copper Deposit (Marginal Folds Basin, Eastern High Atlas, Morocco)

  • Mostapha Bouzekraoui Geosciences, Water, Environnement Laboratory, Earth Sciences Department, Faculty of Sciences, Mohammed V University in Rabat, Morocco
  • Mourad Essalhi Applied Geology Laboratory, Geosciences Department, Faculty of Sciences and Techniques, Moulay Ismail University, Errachidia, Morocco
  • Daoud El Azmi Company Palmines, Palmeraie Industries & Services Group, Casablanca, Morocco
  • Said Ha Applied Geology Laboratory, Geosciences Department, Faculty of Sciences and Techniques, Moulay Ismail University, Errachidia, Morocco
  • Adnane Tobi Applied Geology Laboratory, Geosciences Department, Faculty of Sciences and Techniques, Moulay Ismail University, Errachidia, Morocco
  • Rachid Majidi Company Palmines, Palmeraie Industries & Services Group, Casablanca, Morocco
  • Bilal El Ouaragli Company Palmines, Palmeraie Industries & Services Group, Casablanca, Morocco
  • Mohamed Saadi Geosciences, Water, Environnement Laboratory, Earth Sciences Department, Faculty of Sciences, Mohammed V University in Rabat, Morocco
Keywords: Copper mineralization, sedimentary deposit, Infra-Cenomanian, Merija deposit, marginal folds, Morocco.

Abstract

The Merija copper deposit is located in the Marginal Folds of the Moroccan Eastern High Atlas. It  is a stratiform deposit, hosted in sandstone-conglomerate formations of the Infra-Cenomanian, consisting of copper carbonate and sulphide mineralization (malachite, azurite, traces of chalcopyrite, chalcocite and covellite). This mineralization exhibits different forms: dissemination in the sandstone-conglomerate host rocks and fillings of centimetric veins, sometimes with calcite. Moreover, microscopic examination shows that the mineralization is disseminated in the carbonate matrix, filling of the inter-granular spaces of the sandstone-conglomeratic material. The mineralogical association is composed of: a primary paragenesis with chalcopyrite، a secondary cementation paragenesis with chalcocite and covellite and a secondary oxidation paragenesis with malachite. This latter is the most dominant mineral presenting a micro-fibrous texture surrending the sulphides of the primary and secondary paragenesis, composed of chalcopyrite, chalcocite and covelite. It is associated with a quartz-calcite gangue. The copper mineralization at Merija is heterogeneously distributed within the surrounding sandstone-conglomerate formation due to the diversity of paleocurrents carrying the leached copper. The rich paleocurrents trends S, SW and SE, whereas the poor ones present an N and NW directions. These paleocurrents are derived from a fluvio-deltaic channel system that controlled sedimentary deposition in the area during the Infra-Cenomanian. This sedimentary type mineralization is probably related to a process of alteration and deposition of detrital materials loaded with copper minerals and derived from a protore copper-bearing. This alteration process gave rise to the malachite and azurite mineralization resulting from the replacement phenomenon of chalcopyrite, chalcocite and covellite.

Published
2022-05-23