The Jbel Saghro is interpreted as part of a long-lived silicic large igneous province. The area comprises two lithostructural complexes. The Lower Complex consists of folded metagreywackes and N070–090°E dextral shear zones, which roughly results from a NW–SE to NNW–SSE shortening direction related to a D₁ transpressive tectonic stage. D₁ is also combined with syntectonic plutons emplaced between ca. 615 and 575 Ma. The Upper Complex is defined by ash-flow caldera emplacements, thick and widespread ignimbrites, lavas and volcaniclastic sedimentary rocks with related intrusives that were emplaced in three main magmatic flare ups at ca. 575, 565 and 555 Ma. It lies unconformably on the Lower Complex units and was affected by a D₂ trantensive tectonic stage. Between 550 and 540 Ma, the magmatic activity became slightly alkaline and of lower extent. Ore deposits show specific features, but remain controlled by the same structural setting: a NNW–SSE shortening direction related to both D₁ and D₂ stages. Porphyry Au(–Cu–Mo) and intrusion-related gold deposits were emplaced in an earlier stage between 580 and 565 Ma. Intermediate sulfidation epithermal deposits may have been emplaced during lull periods after the second and (or) the third flare-ups (560–550 Ma). Low sulfidation epithermal deposits were emplaced late during the felsic alkaline magmatic stage (550–520 Ma). The D₂ stage, therefore, provided extensional structures that enabled fluid circulations and magmatic-hydrothermal ore forming processes.

The giant Tizert copper deposit is considered as the largest copper resource in the western Anti-Atlas (Morocco). The site is characterized by Cu mineralization carried by malachite, chalcocite, covellite, bornite and chalcopyrite; azurite is not observed. The host rocks are mainly limestones (Formation of Tamjout Dolomite) and sandstones/siltstones (Basal Series) of the Ediacaran/Cambrian transition. The supergene enrichment is most likely related to episodes of uplift/doming (last event since 30 Ma), which triggered the exhumation of primary/hypogene mineralization (chalcopyrite, pyrite, galena, chalcocite I and bornite I), generating their oxidation and the precipitation of secondary/supergene sulfides, carbonates and Fe-oxyhydroxides. The Tizert supergene deposit mainly consists of (i) a residual patchwork of laterite rich in Fe-oxyhydroxides; (ii) a saprolite rich in malachite, or “green oxide zone” where primary structures such as stratification are preserved; (iii) a cementation zone containing secondary sulfides (covellite, chalcocite II and bornite II). The abundance of Cu carbonates results from the rapid neutralization of acidic meteoric fluids, due to oxidation of primary sulfides, by carbonate host rocks. Chlorite is also involved in the neutralization processes in the sandstones/siltstones of the Basal Series, in which supergene clays, such as kaolinite and smectites, subsequently precipitated. At Tizert, as can be highlighted in other supergene Cu-deposits around the world, azurite is absent due to low pCO₂ and relatively high pH conditions. In addition to copper, Ag enrichment is also observed in weathered rocks; Fe-oxyhydroxides contain high Zn, As, and Pb contents. However, these secondary enrichments are quite low compared to Cu in the whole Tizert site, which is therefore, considered as relatively homogeneous.

Located in the southeastern region of Morocco, the Zagora area mainly relies on groundwater as a source of water supply. However, this groundwater is often of concern, due to the limited recharge and unfavorable geological conditions for the development of the aquifer. Despite this, private wells in the Zagora ditch reveal relatively rich water resources. Geochemical and isotopic studies were conducted in the area to understand the origin of the groundwater and its salinity, aiding in informed water management strategies to assist in better planning and regulation of well construction, as well as in mitigating the impacts of high salinity on local water supply and agricultural systems. The results show that the water quality varies, with some wells having conductivity values in excess of 5 mS/cm. Most groundwater samples have high salinity and low pH due to the CO₂ dissolved in groundwater. Geochemical analysis indicated two chemical facies: chloride–sulfate calcic/magnesic and bicarbonate calcic/magnesic. The presence of Na⁺ and Cl⁻ indicated that the origin of these two elements in these waters was the dissolution of halite, with some samples showing an enrichment of Na⁺ compared to Cl⁻. This could be attributed to cation exchange. The concentration of Ca²⁺ and HCO₃⁻ suggested that their origin is the dissolution of calcite and the weathering of calcium silicate minerals such as plagioclase. The isotopic analysis showed that the δ¹⁸O values ranged from −10.98‰ to −8.54‰, and δ²H values ranged from −75.9‰ to −62.3‰. This indicated that the groundwater originated from the High Atlas with a recharge altitude between 2600 m and 2800 m. The groundwater flows into the graben through fissures and regional fault networks.

This work provides an overview of the geological, geochemical, and metallogenic data available up to date on the Moroccan massive sulphide deposits, including some new results, and then discusses the evidences for the epigenetic and syngenetic hypotheses. All of the ore deposits are located within a crustal block located at the intersection between two major shear zones and are characterized by a sustained and long-lived magmatic activity. The ore deposits are located within second-order shear zones, which played an important role in controlling the geometry of the mineralization. The mineralization lacks the unequivocal textural and structural features that are indicative of a sedimentary or diagenetic origin, and a syntectonic to late-tectonic pyrite-rich assemblage is superimposed on an earlier, pretectonic to syntectonic pyrrhotite-rich mineralization. Each deposit has a distinctive pyrrhotite sulfur isotopic signature, while the sulfur isotopic signature of pyrite is similar in all deposits. Lead isotopes suggest a shift from a magmatic source during the pyrrhotite-rich mineralization to a source that is inherited from the host shales during the pyrite-rich mineralization. The O/H isotopic signatures record a predominance of fluids of metamorphic derivation. These results are consistent with a model in which an earlier pyrrhotite-rich mineralization, which formed during transtension, was deformed and then remobilized to pyrite-rich mineralization during transpression.

The genesis of the base-metal massive sulfide deposits hosted within the Moroccan Hercynian Jebilet and Guemassa Massifs is still under debate. No consensus currently exists between the two models that have been proposed to explain the deposits, i.e., (1) syngenetic volcanogenic massive sulfide mineralization, and (2) synmetamorphic tectonic fluid-assisted epigenetic mineralization. Conversely, researchers agree that all Hercynian massive sulfide deposits in Morocco are deformed, even though 3D structural mapping at the deposit scale is still lacking. Therefore, while avoiding the use of a model-driven approach, the main aim of this contribution is to establish a first-order structural pattern and the controls of the Hajjar base metal deposit. We used a classical structural geology toolbox in surface and subsurface mining work to image finite strain at different levels. Our data demonstrate that: i) the Hajjar area is affected by a single foliation plane (not two) which developed during a single tectonic event encompassing a HT metamorphism. This syn-metamorphic deformation is not restricted to the Hajjar area, as it is widespread at the western Meseta scale, and it occurred during Late Carboniferous times; ii) the Hajjar ore deposit is hosted within a regional transpressive right-lateral NE-trending shear zone in which syn- to post-metamorphic ductile to brittle shear planes are responsible for significant inflexion (or virgation) of the foliation yielding an anastomosing pattern within the Hajjar shear zone. Again, this feature is not an exception, as various Late Carboniferous-Permian regional scale wrenching shear zones are recognized throughout the Hercynian Meseta orogenic segment. Finally, we present several lines of evidence emphasizing the role of deformation in terms of mechanical and fluid-assisted ore concentrations.

The Khzama ophiolite is a highly dismembered complex located in the Siroua inlier of the Moroccan Anti-Atlas Belt. It consists of ultramafic rocks, cumulate gabbros, sheeted dikes, pillow lavas, and an overlying volcano-sedimentary sequence. Three main tectonic slices of sheeted dike complexes are studied in detail along three rivers, exposing well preserved outcrops where individual dikes are clearly distinguishable from the intruded host rock (Assif n’Tinzla, Assif n’Tasriwine, and Assif n’Iriri). Sheeted dikes of the Khzama ophiolitic complex are basaltic to andesitic in composition, displaying a clear sub-alkaline nature. We identify two sets of dikes that originate from lower High-Ti series (HTS) lavas and overlying upper Low-Ti series (LTS) lava. The immobile trace-element signatures of these rocks point to a genesis on a backarc environment with magmas sourced in a supra-subduction zone (SSZ) at the spinel peridotite zone. The obtained SHRIMP U-Pb data of the gabbro represent the first radiometric age of zircon extracted from the mafic rocks that were intruded by the sheeted dike complex of the Khzama ophiolite. These grains yield a concordia age of 763 ± 5 Ma, which is consistent with the 761.1 + 1.9/−1.6 and 762 + 1/−2 Ma U-Pb zircon ages of plagiogranites of Siroua. Based on their mineralogy, modal proportions, and major element chemistry, the felsic dikes are classified as high silica–low alumina trondhjemites or plagiogranites. These plagiogranites were likely formed by the partial melting of mafic rocks rather than by extreme fractional crystallization. A plagiogranite dated at 777 ± 4.7 Ma (U-Pb on zircon) is significantly older than the ca. 762 Ma plagiogranites previously recorded for the Khzama locality, suggesting a long-lived supra-subduction zone (SSZ) with conditions for the hydrous melting of mafic rocks.