[ Etudes pétrographique et minéralogique des minéralisations sulfurées polymétalliques des formations viséennes de la faille des Jbala: Nature et origine de la minéralisation (District El Hammam, Maroc Central) ]
Volume 42, Issue 3, May 2024, Pages 465–493
Fouad Lotfi1 and Aissa Mohamed2
1 Université Ibn Zohr, Faculté Polydisciplinaire de Taroudant, Hay El Mohammadi (Lastah), B.P : 271, 83 000 Taroudant, Morocco
2 Faculté des sciences Meknès, Université Moulay Ismaïl, Morocco
Original language: French
Copyright © 2024 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
In the district of EI Hammam and precisely in the sector of Ticht Ouguas and along the fault of Jbala, which materializes in this place the abnormal contact between the anticlinorium of Khouribga-Oulmès and the synclinorium of Fourhal-TeIt, the presence sulphides disseminated in the sediments, the discovery of a major gravimetric anomaly in these sectors and above all the recognition and description, for the first time, of volcanic pillow lavas (pillow lavas), prompted the undertaking of prospecting for sulphide deposits. In this sense, two cored boreholes (SCJB1, SCJB2) of a few hundred m were implanted in the valley of the Boutoukret wadi upstream of the mine, almost on the route of the Jbala fault. The region of the Jbala fault has experienced multiple geological events, which can be summarized in two major stages. The first stage corresponds to Visean turbiditic sedimentation in an active context of synsedimentary tectonics, followed by a second stage which corresponds to a major deformation with a NE-SW structure (post-Visean event) materialized by the functioning of the inherited fault, a tourmalinization (introduction of boron probably in relation to a thermal flux of deep origin (placement of the Achemèche granite), shear under conditions of brittle deformation, and finally a placement of sulphides. The petrographic and mineralogical study of a certain number of samples from these drillings supplemented with those of surface made it possible to recognize petrographic facies (1) of the sedimentary rocks corresponding to an alternation of limestone benches, sandstones and dark pelites having undergone slight metamorphism hardly exceeding the degree of greenschist, (2) igneous rocks: diorites, dolerites and pillow lavas probably similar to a keratophyre, and (3) sulphides present along the entire length of the boreholes. Depending on the arrangement and lithological nature of the formations that host these sulphides, several types have been distinguished: either disseminated (essentially pyrite and pyrrhotite) or in fine laminae predominantly pyritic, or polymetallic (pyrite, pyrrhotite, chalcopyrite and especially sphalerite) associated with carbonate levels, more or less skarnified and later in fissures parallel with the sulphides of the fluorite veins.
Author Keywords: Central Morocco, Jbala Fault, sulphides, skarns.
Volume 42, Issue 3, May 2024, Pages 465–493
Fouad Lotfi1 and Aissa Mohamed2
1 Université Ibn Zohr, Faculté Polydisciplinaire de Taroudant, Hay El Mohammadi (Lastah), B.P : 271, 83 000 Taroudant, Morocco
2 Faculté des sciences Meknès, Université Moulay Ismaïl, Morocco
Original language: French
Copyright © 2024 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
In the district of EI Hammam and precisely in the sector of Ticht Ouguas and along the fault of Jbala, which materializes in this place the abnormal contact between the anticlinorium of Khouribga-Oulmès and the synclinorium of Fourhal-TeIt, the presence sulphides disseminated in the sediments, the discovery of a major gravimetric anomaly in these sectors and above all the recognition and description, for the first time, of volcanic pillow lavas (pillow lavas), prompted the undertaking of prospecting for sulphide deposits. In this sense, two cored boreholes (SCJB1, SCJB2) of a few hundred m were implanted in the valley of the Boutoukret wadi upstream of the mine, almost on the route of the Jbala fault. The region of the Jbala fault has experienced multiple geological events, which can be summarized in two major stages. The first stage corresponds to Visean turbiditic sedimentation in an active context of synsedimentary tectonics, followed by a second stage which corresponds to a major deformation with a NE-SW structure (post-Visean event) materialized by the functioning of the inherited fault, a tourmalinization (introduction of boron probably in relation to a thermal flux of deep origin (placement of the Achemèche granite), shear under conditions of brittle deformation, and finally a placement of sulphides. The petrographic and mineralogical study of a certain number of samples from these drillings supplemented with those of surface made it possible to recognize petrographic facies (1) of the sedimentary rocks corresponding to an alternation of limestone benches, sandstones and dark pelites having undergone slight metamorphism hardly exceeding the degree of greenschist, (2) igneous rocks: diorites, dolerites and pillow lavas probably similar to a keratophyre, and (3) sulphides present along the entire length of the boreholes. Depending on the arrangement and lithological nature of the formations that host these sulphides, several types have been distinguished: either disseminated (essentially pyrite and pyrrhotite) or in fine laminae predominantly pyritic, or polymetallic (pyrite, pyrrhotite, chalcopyrite and especially sphalerite) associated with carbonate levels, more or less skarnified and later in fissures parallel with the sulphides of the fluorite veins.
Author Keywords: Central Morocco, Jbala Fault, sulphides, skarns.
Abstract: (french)
Dans le district d’EI Hammam et précisément dans le secteur de Ticht Ouguas et le long de la faille des Jbala, qui matérialise à cet endroit le contact anormal entre l’anticlinorium de Khouribga-Oulmès et le synclinorium de Fourhal-TeIt, la présence de sulfures disséminées dans les sédiments, la mise en évidence d’une importante anomalie gravimétrique dans ces secteurs et surtout la reconnaissance et la description, pour la première fois, de laves volcaniques en coussins (pillow lavas), ont incité à entreprendre des travaux de prospections à la recherche d’amas sulfurés. Dans ce sens, deux sondages carottés (SCJB1, SCJB2) de quelques centaines de m ont été implantés dans le vallon de l’oued Boutoukret en amont de la mine, quasiment sur le tracé de la faille des Jbala. La région de la faille des Jbala a connu de multiples évènements géologiques, qui peuvent être résumés en deux grands stades. Le premier stade correspond à une sédimentation turbiditique viséenne dans un contexte actif de tectonique synsédimentaire, suivi par un second stade qui correspond à une déformation majeure avec une structure NE-SW (évènement post-viséen) matérialisé par le fonctionnement de la faille héritée, une tourmalinisation (introduction du bore en relation probablement avec un flux thermique d’origine profonde (mise en place du granite d’Achemèche), un cisaillement dans des conditions de déformations cassantes, et en fin une mise en place des sulfures. L’étude pétrographique et minéralogique d’un certain nombre d’échantillons provenant de ces sondages complétée à ceux de surface a permis de reconnaître des faciès pétrographiques (1) des roches sédimentaires correspondant à une alternance de bancs calcaires, grés et de pélites sombres ayant subi un léger métamorphisme ne dépassant guère le degré du schiste vert, (2) des roches magmatiques: diorites, dolèrites et pillow lavas vraisemblablement similaire à un kératophyre, et (3) des sulfures présents sur toute la longueur des sondages. Selon l’agencement et la nature lithologique des formations qui encaissent ces sulfures, plusieurs types ont été distingués: soit disséminées (essentiellement pyrite et pyrrhotite) ou en lamines fines à dominance pyriteuse, soit polymétallique (pyrite, pyrrhotite, chalcopyrite et surtout à sphalérite) associés à des niveaux carbonatés, plus ou moins skarnifîés et tardivement en fissures parallèlement avec les sulfures des filons de fluorine.
Author Keywords: Maroc central, Faille des Jbala, sulfures, skarns.
How to Cite this Article
Fouad Lotfi and Aissa Mohamed, “Petrographic and mineralogical studies of the polymetallic sulphide mineralization of the Visean formations of the Jbala fault: Nature and origin of mineralization (El Hammam District, Central Morocco),” International Journal of Innovation and Applied Studies, vol. 42, no. 3, pp. 465–493, May 2024.
