The Bou Azzer inlier of the Anti-Atlas in Morocco represents a geological window into Proterozoic... more The Bou Azzer inlier of the Anti-Atlas in Morocco represents a geological window into Proterozoic basement surrounded by a discordantly overlying infra-Cambrian to Paleozoic cover sequence. The serpentinization at Bou Azzer occured in two phases. Pseudomorphic oceanic serpentinisation, represented by the isotropic serpophite preserving the primary form of olivine crystals, affected the entire series homogeneously, often with fibro-struck needles antigorite. Brucite is fairly common, observed as inclusions in the serpentine. Secondly, tectonic continental serpentinisation occurred during subduction and obduction of the ophiolite, producing lizardite and chrysotile (Wafik, 2001). We focused our work on field investigation by geological and numerical mapping in many cross-sections and sampling of the Mechoui, Ambed, Inguijem and Ait Ahmane massifs. Our laboratory investigation was based on petrographic, metallographic and geochemical studies. We observed that the serpentinization of ul...
Ultramafic rocks are essentially constituted by silicates of magnesium: forsterite, and/or Diopsi... more Ultramafic rocks are essentially constituted by silicates of magnesium: forsterite, and/or Diopside-enstatite; who's the most common hydrothermal alteration are the serpentinization. To Bou Azzer, the serpentinisation affected almost all of the ultrabasic rocks. Among the phenomena bound to the serpentinisation observed on the ground, we distinguish the magnesium deposits (Carbonated serpentinite). These magnesian deposits correspond to veins taken in serpentinized peridotites either realizes the contact between serpentinites and ultrabasic and basic cumulats. These veins of some centimeters a few meters away from power concentrate essentially in the regions of Ait Ahmane, Ingujjem and Ambed and are formed by massive or brecciated magnesite or in cauliflower. The petrography ic and mineralogical studies of the deposits of magnesite of Bou Azzer, reveal mainly two different mechanisms: The replacement metasomatic in situ of the serpentine and the filling of fracture by circulatio...
ABSTRACT The Cu–Au deposit of the Talat n’Imjjad occurrence, southwestern Azegour mine, western H... more ABSTRACT The Cu–Au deposit of the Talat n’Imjjad occurrence, southwestern Azegour mine, western High Atlas of Morocco, is situated in a NW trending quartz vein along a shear zone in quartz diorite host rocks. The recently discovered shear zone, ~200-m long, NW–SE trending, so-called Talat n’Imjjad vein system of Cu–Au–Bi–Te–Se mineralization that crosscuts the Al Medinet quartz diorite, represents a landmark in regional metallogeny. This region has long been known for its polymetallic ore deposits, with the historical Mo–Cu–W mine of Azegour and Pb–Zn–Ag mine of Erdouz. The economic sulfide enrichment is often hosted by breccias and quartz veins in the ductile shear zone. Samples from the field surface and boreholes show macro- and microscopic evidence of shearing such as S-C fabrics and microshear planes. The quartz diorite was deformed and mylonitized, then the igneous texture was modified. On the basis of textures, mineral assemblages, and hydrothermal alteration, four stages were documented and could be distinguished: (1) quartz I–sericite–chlorite–epidote pre-ore stage; (2) chlorite–quartz II–calcite–pyrite ore stage; (3) native bismuth–bismuthinite–emplectite–wittichenite–(tsumoite–laitakarite)–chalcopyrite–sphalerite–native gold–calcite ore stage II; and (4) bismuthite–hematite–malachite–covellite post-ore stage. Bi-chalcogenides are considered as pathfinders for gold in Au–quartz veins. The association of gold with Bi-minerals is linked to the role of Bimelt as scavenger for gold. Tellurides and selenides are also the best indicators of the magmatic signature. The alteration types of the wall rocks include seritization, silicification, chloritization, carbonatization, and propylitization. The auriferous shear zone of Talat n’Imjjad represents a newly discovered occurrence in the western High Atlas characterized by its mineralogy, paragenetic sequence, hydrothermal alteration, and magmatic and structural control of the deposit of sulfide minerals.
The Bleïda copper deposit is located in the southeastern part of the Bou Azzer-El Graara Precambr... more The Bleïda copper deposit is located in the southeastern part of the Bou Azzer-El Graara Precambrian inlier, within the Lower Neoproterozoic Tachdamt-Bleïda platform. Two types of mineralization are distinguished, a stratiform “north type”, which predates the main Pan-African event, and a hydrothermal “south type” controlled by late Pan-African brittle faults.
Chromite deposits associated with the ophiolites of the Bou Azzer-El Graara inlier display two ty... more Chromite deposits associated with the ophiolites of the Bou Azzer-El Graara inlier display two types : i) a small podiform type associated with PGE and concentrated in the eastern part of the inlier within the transitional series and cumulates ; ii) a second, large sized type recently discovered in the lower part of the ophiolite, associated with primary (pentlandite) and secondary Ni minerals (polydymite, orcélite, millerite, maucherite) formed during serpentinization.
Oxidized copper opencast mining in the Lower Cambrian to the NE of the Bou Azzer-El Graara Precam... more Oxidized copper opencast mining in the Lower Cambrian to the NE of the Bou Azzer-El Graara Precambrian inlier. The Cambrian formations include basic lavas. The mineralized deposits occur at the intersection of two Variscan structures, i.e. NW-trending folds and a post-dating, SE-verging thrust.
The Bou Azzer inlier of the Anti-Atlas in Morocco represents a geological window into Proterozoic... more The Bou Azzer inlier of the Anti-Atlas in Morocco represents a geological window into Proterozoic basement surrounded by a discordantly overlying infra-Cambrian to Paleozoic cover sequence. The serpentinization at Bou Azzer occured in two phases. Pseudomorphic oceanic serpentinisation, represented by the isotropic serpophite preserving the primary form of olivine crystals, affected the entire series homogeneously, often with fibro-struck needles antigorite. Brucite is fairly common, observed as inclusions in the serpentine. Secondly, tectonic continental serpentinisation occurred during subduction and obduction of the ophiolite, producing lizardite and chrysotile (Wafik, 2001). We focused our work on field investigation by geological and numerical mapping in many cross-sections and sampling of the Mechoui, Ambed, Inguijem and Ait Ahmane massifs. Our laboratory investigation was based on petrographic, metallographic and geochemical studies. We observed that the serpentinization of ul...
Ultramafic rocks are essentially constituted by silicates of magnesium: forsterite, and/or Diopsi... more Ultramafic rocks are essentially constituted by silicates of magnesium: forsterite, and/or Diopside-enstatite; who's the most common hydrothermal alteration are the serpentinization. To Bou Azzer, the serpentinisation affected almost all of the ultrabasic rocks. Among the phenomena bound to the serpentinisation observed on the ground, we distinguish the magnesium deposits (Carbonated serpentinite). These magnesian deposits correspond to veins taken in serpentinized peridotites either realizes the contact between serpentinites and ultrabasic and basic cumulats. These veins of some centimeters a few meters away from power concentrate essentially in the regions of Ait Ahmane, Ingujjem and Ambed and are formed by massive or brecciated magnesite or in cauliflower. The petrography ic and mineralogical studies of the deposits of magnesite of Bou Azzer, reveal mainly two different mechanisms: The replacement metasomatic in situ of the serpentine and the filling of fracture by circulatio...
ABSTRACT The Cu–Au deposit of the Talat n’Imjjad occurrence, southwestern Azegour mine, western H... more ABSTRACT The Cu–Au deposit of the Talat n’Imjjad occurrence, southwestern Azegour mine, western High Atlas of Morocco, is situated in a NW trending quartz vein along a shear zone in quartz diorite host rocks. The recently discovered shear zone, ~200-m long, NW–SE trending, so-called Talat n’Imjjad vein system of Cu–Au–Bi–Te–Se mineralization that crosscuts the Al Medinet quartz diorite, represents a landmark in regional metallogeny. This region has long been known for its polymetallic ore deposits, with the historical Mo–Cu–W mine of Azegour and Pb–Zn–Ag mine of Erdouz. The economic sulfide enrichment is often hosted by breccias and quartz veins in the ductile shear zone. Samples from the field surface and boreholes show macro- and microscopic evidence of shearing such as S-C fabrics and microshear planes. The quartz diorite was deformed and mylonitized, then the igneous texture was modified. On the basis of textures, mineral assemblages, and hydrothermal alteration, four stages were documented and could be distinguished: (1) quartz I–sericite–chlorite–epidote pre-ore stage; (2) chlorite–quartz II–calcite–pyrite ore stage; (3) native bismuth–bismuthinite–emplectite–wittichenite–(tsumoite–laitakarite)–chalcopyrite–sphalerite–native gold–calcite ore stage II; and (4) bismuthite–hematite–malachite–covellite post-ore stage. Bi-chalcogenides are considered as pathfinders for gold in Au–quartz veins. The association of gold with Bi-minerals is linked to the role of Bimelt as scavenger for gold. Tellurides and selenides are also the best indicators of the magmatic signature. The alteration types of the wall rocks include seritization, silicification, chloritization, carbonatization, and propylitization. The auriferous shear zone of Talat n’Imjjad represents a newly discovered occurrence in the western High Atlas characterized by its mineralogy, paragenetic sequence, hydrothermal alteration, and magmatic and structural control of the deposit of sulfide minerals.
The Bleïda copper deposit is located in the southeastern part of the Bou Azzer-El Graara Precambr... more The Bleïda copper deposit is located in the southeastern part of the Bou Azzer-El Graara Precambrian inlier, within the Lower Neoproterozoic Tachdamt-Bleïda platform. Two types of mineralization are distinguished, a stratiform “north type”, which predates the main Pan-African event, and a hydrothermal “south type” controlled by late Pan-African brittle faults.
Chromite deposits associated with the ophiolites of the Bou Azzer-El Graara inlier display two ty... more Chromite deposits associated with the ophiolites of the Bou Azzer-El Graara inlier display two types : i) a small podiform type associated with PGE and concentrated in the eastern part of the inlier within the transitional series and cumulates ; ii) a second, large sized type recently discovered in the lower part of the ophiolite, associated with primary (pentlandite) and secondary Ni minerals (polydymite, orcélite, millerite, maucherite) formed during serpentinization.
Oxidized copper opencast mining in the Lower Cambrian to the NE of the Bou Azzer-El Graara Precam... more Oxidized copper opencast mining in the Lower Cambrian to the NE of the Bou Azzer-El Graara Precambrian inlier. The Cambrian formations include basic lavas. The mineralized deposits occur at the intersection of two Variscan structures, i.e. NW-trending folds and a post-dating, SE-verging thrust.
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