4 results on '"Moundi, Younes"'
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2. Co-Ni-arsenide mineralisation in the Bou Azzer district (Anti-Atlas, Morocco): genetic model and tectonic implications
- Author
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Johann Tuduri, Sizaret Stanislas, Moundi Younes, Kouzmanov Kalin, Alain Chauvet, Karfal Abdelhak, El Hassani Abdelfattah, Tourneur Enora, Paquez Camille, Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), University of Geneva [Switzerland], Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Laboratoire GéoSciences Réunion (LGSR), Université de La Réunion (UR)-Institut de Physique du Globe de Paris, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Métallogénie - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Managem Group and CTT, and Tellus Program of CNRS/INSU
- Subjects
Co-Ni-As (-Au-Ag) Bou Azzer district ,Vein Massive arsenide ores ,Lithology ,020209 energy ,Geochemistry ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Context (language use) ,02 engineering and technology ,010502 geochemistry & geophysics ,01 natural sciences ,Geochemistry and Petrology ,Breccia ,Genetic model ,Tectonic implications ,0202 electrical engineering, electronic engineering, information engineering ,Hydrothermalism ,0105 earth and related environmental sciences ,Transtension ,Geology ,15. Life on land ,Diorite ,[SDU]Sciences of the Universe [physics] ,Economic Geology ,Vein (geology) ,Mylonite ,Serpentinite - Abstract
International audience; The two main types of mineralisation in the Co-Ni-As Bou Azzer district, i.e., “contact” mineralisation” and “cross-cutting” structures have been re-defined based on new field, structural, textural and mineralogical observations. The main orebodies consists of elongated lenses of massive Ni-Co-Fe arsenide minerals. These lenses occur in a core of carbonate or siliceous gangue and are almost exclusively located along the contact between serpentinite and a quartz diorite intrusion. Vein systems, cross-cutting the different lithologies, are ore-bearing only along segments in contact with the serpentinite and/or the massive mineralisation. The two orebody types share a rather similar mineralisation history, starting with a Ni-rich arsenide stage (mainly expressed within the massive mineralisation), followed by a massive Co-arsenide stage recognised in both mineralisation styles, and ending with Fe-rich arsenide and base metal sulphide stage.Detailed field observations, microstructural, tectonic, textural and mineralogical analyses led us to propose a genetic model for the Bou Azzer ore district in which massive mineralisation was formed by alteration and transformation of previously formed breccia levels composed of serpentinite (transformed to gangue) and magnetite/spinel (transformed to Co-Ni arsenide minerals) fragments. Inversely, a tectono-hydrothermal event controlled by a NE oriented transtension generated the vein system, associated certainly with partial leaching and reconcentration of metals from the massive mineralisation because veins are principally mineralised when crossing massive orebodies. We discuss a possible temporal continuum between the two mineralisation styles: massive mineralisation, coeval with serpentinisation (serpentine neoformation), is related to the transformation of brecciated lenses and vein mineralisation is formed as an infill of large fractures during transtensive tectonics. This model has significant tectonic implications, because serpentinite breccia lenses, favourable high-permeability environment for the massive mineralisation formation, can be compared to ophicalcic rocks developed in a context of mantle exhumation by detachment. Two types of textures can be differentiated within the massive mineralisation: i) Brecciated Massive Mineralisation, developed in the core of ophicalcic levels, and ii) Laminated Massive Mineralisation, supposed to form within ancient mylonitic serpentinite levels corresponding to intensive deformation zones. Although the geodynamic significance will not be addressed in this article, we propose and discuss an alternative model in which the presence of exhumed mantle rocks allows the formation of specific massive arsenide deposits.
- Published
- 2021
3. Cobalt–nickel–copper arsenide, sulfarsenide and sulfide mineralization in the Bou Azzer window, Anti-Atlas, Morocco: one century of multi-disciplinary and geological investigations, mineral exploration and mining
- Author
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Ikenne, Moha, primary, Souhassou, Mustapha, additional, Saintilan, Nicolas J., additional, Karfal, AbdelHaq, additional, Hassani, Abdelfattah E. L., additional, Moundi, Younes, additional, Ousbih, Mehdi, additional, Ezzghoudi, Mohamed, additional, Zouhir, Mohamed, additional, and Maacha, Lhou, additional
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- 2020
- Full Text
- View/download PDF
4. Cobalt–nickel–copper arsenide, sulfarsenide and sulfide mineralization in the Bou Azzer window, Anti-Atlas, Morocco: one century of multi-disciplinary and geological investigations, mineral exploration and mining
- Author
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Ikenne, Moha, Souhassou, Mustapha, Saintilan, Nicolas J., Karfal, AbdelHaq, Hassani, Abdelfattah E. L., Moundi, Younes, Ousbih, Mehdi, Ezzghoudi, Mohamed, Zouhir, Mohamed, and Maacha, Lhou
- Abstract
The Bou Azzer mining district in the central part of the Anti-Atlas belt, Morocco, is renowned worldwide for its serpentinized Neoproterozoic ophiolitic complex that hosts peculiar cobalt-dominated and nickel-rich Co–Ni–Fe arsenide and sulfarsenide deposits with significant credits of gold and copper. The Bou Azzer central mine and its satellite deposits, which are spatially associated with serpentinite bodies and tectonically controlled, generally form breccias at the contact between serpentinites and more competent rock types (e.g. diorite) but may also comprise anastomosing vein and tension gashes networks rooted in the serpentinites and breaching into the competent rocks. A consensus on a genetic model for Bou Azzer has not been reached given the most controversial and still highly debated topics dealing with the absolute age of mineralization, and the identification of the source(s) of metals and arsenic. Here, within the geological framework of the Bou Azzer window and the geodynamic history in the Anti-Atlas, we summarize the key features of ore mineralogy, textures, paragenetic sequence and district-scale metal zonation. Using knowledge based on the current state of research – until high-precision and robust geochronological data are produced and permit a refinement of the genetic model – the key parameters for the origin of the Bou Azzer ores are: (1) arsenides of Ni and Co, which are followed by Co–Ni-sulfarsenides and Cu-sulfides, initiating a sequence of mineralization with precipitation controlled by the parameters mentioned in (2)–(4); (2) hydrothermal high salinity fluids (>30 wt% total salt eq.) fostering leaching of Co and Ni from debated source rocks and their transport as highly soluble chloride complexes; (3) dilution and cooling of those fluids from <320 to <200°C; (4) variable redox conditions that would control the progressive oxidation of As from the arsenide stage (As1−) to the sulfarsenide stage (As3+); (5) unlike Neoproterozoic metalliferous and As-rich black shales, serpentinites fail to convincingly stand as a robust source of As despite being a reasonable source rock for Ni and Co; (6) the controversial U–Pb and Sm–Nd dates of brannerite and carbonate, respectively, although arguing in favour of an Hercynian timing of mineralization, do not preclude the possibility of a primary Pan-African mineralization (<615 Ma) and/or at c.540 Ma, followed by remobilization of a pre-existing mineralization during Hercynian events.
- Published
- 2021
- Full Text
- View/download PDF
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