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<p>The Tazekka Variscan Massif, located in the northeastern part of the Middle Atlas Belt in Morocco, is a significant geological structure hosting a wide range of polymetallic vein deposits, including lead–zinc, copper, barium, iron, silver, gold, and antimony, mainly within Paleozoic rocks. These mineralizations exhibit lateral mineralogical zonation between two domains of the Tazekka Inlier and are closely associated with a complex tectonic evolution. To better understand the metallogenic and structural framework, an integrated approach was applied, combining paleostress analysis based on fault-slip data inversion with detailed field observations of slickenside-bearing faults. The results reveal four main tectono-metallogenic phases. The first phase involves a NW–SE compression characterized by the development of N30–50 fracture cleavages, N150–170 sinistral strike-slip faults, and N10–40 reverse faults with strike-slip components, mineralized with barite and iron-rich quartz. The second phase, dominated by strike-slip deformation, reflects a NE–SW compressive direction and NW–SE extension, resulting in N20–40 dextral and N60–80 sinistral strike-slip faults, as well as N150–170 reverse faults with dextral oblique slip. These structures are associated with antimony, barite, and sulfide veins within a milky quartz gangue. The third phase corresponds to a mixed compressional-extensional regime with a sub-meridional to NNW–SSE shortening direction and ENE–WSW extension. It is marked by N60–80 dextral-reverse faults, N10–30 sinistral strike-slip faults, and N130–150 dextral-normal faults, which host sulfides, barite, iron oxides, and hydroxides. The final phase reflects an extensional regime with NW-directed stretching and vertical shortening, characterized by N30–60 normal faults with a dextral component. These faults are filled with barite and are responsible for the tilting of Paleozoic rocks. This last phase is attributed to Late Triassic–Early Jurassic rifting that influenced regional basin dynamics and hydrothermal fluid circulation.</p>

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Late-to-Post-Variscan deformation phases and paleostress evolution in the Tazekka Variscan Massif (eastern Meseta, Morocco): structural control on vein-type mineralization

  • 期刊论文

  • 发表日期：

    2025年9月5日

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  • Youssef Gharmane,
  • Saïd Hinaje,
  • Youness Taybi,
  • Saadia El Hajjami,
  • Hicham Gueddari,
  • Driss Yaagoub,
  • Samir Amrani,
  • Abdelali Gouiss,
  • Abdelhay El Omari,
  • Mohamed El Fartati

摘要

The Tazekka Variscan Massif, located in the northeastern part of the Middle Atlas Belt in Morocco, is a significant geological structure hosting a wide range of polymetallic vein deposits, including lead–zinc, copper, barium, iron, silver, gold, and antimony, mainly within Paleozoic rocks. These mineralizations exhibit lateral mineralogical zonation between two domains of the Tazekka Inlier and are closely associated with a complex tectonic evolution. To better understand the metallogenic and structural framework, an integrated approach was applied, combining paleostress analysis based on fault-slip data inversion with detailed field observations of slickenside-bearing faults. The results reveal four main tectono-metallogenic phases. The first phase involves a NW–SE compression characterized by the development of N30–50 fracture cleavages, N150–170 sinistral strike-slip faults, and N10–40 reverse faults with strike-slip components, mineralized with barite and iron-rich quartz. The second phase, dominated by strike-slip deformation, reflects a NE–SW compressive direction and NW–SE extension, resulting in N20–40 dextral and N60–80 sinistral strike-slip faults, as well as N150–170 reverse faults with dextral oblique slip. These structures are associated with antimony, barite, and sulfide veins within a milky quartz gangue. The third phase corresponds to a mixed compressional-extensional regime with a sub-meridional to NNW–SSE shortening direction and ENE–WSW extension. It is marked by N60–80 dextral-reverse faults, N10–30 sinistral strike-slip faults, and N130–150 dextral-normal faults, which host sulfides, barite, iron oxides, and hydroxides. The final phase reflects an extensional regime with NW-directed stretching and vertical shortening, characterized by N30–60 normal faults with a dextral component. These faults are filled with barite and are responsible for the tilting of Paleozoic rocks. This last phase is attributed to Late Triassic–Early Jurassic rifting that influenced regional basin dynamics and hydrothermal fluid circulation.