The Imourkhssen porphyry Cu±Mo±Au±Ag deposit is located at the Ouzellagh-Siroua Salient (OSS) straddling the boundary between the central Anti-Atlas and the central High Atlas. It is characterized by a typical porphyry-style mineralization. The volcanic rocks are intruded by numerous magmatic rocks of the Ouarzazate Group (580–539 Ma), referred to as the Late Ediacaran magmatic suites (LEMS). Of these, the Askaoun, Imourkhssen, and Imourgane granites are the most significant as they are related to the porphyry mineralization. The entire set is intruded by the Zaghar mafic dyke swarms. Zircon U-Pb dating of the Imourkhssen granite and the ore-bearing granite porphyry shows that these intrusive rocks were emplaced at 558 ± 1 and 550 ± 2 Ma, respectively. Moreover, the whole-rock major and trace element geochemistry reveal a high-K calc-alkaline I-type composition, consistent with an emplacement in a post-collisional setting under a trans-tensional tectonic regime. Ore bodies are hosted by the Askaoun granodiorite as well as the Imourgane granite. The mineralization occurs as fine-grained dissemination and infills of hydrothermally altered NNE–SSW to N–S trending veins and veinlets. Ore-related hydrothermal alteration consists of potassic, chlorite-sericite, serecitic, and propylitic mineral assemblages along with pervasive silicification and pyritization, providing a porphyry-style alteration pattern. The ore periods comprise supergene and magmatic-hydrothermal periods. The latter includes primary dissemination and secondary NNE–SSW to N–S ore-bearing system stages. The occurrence of molybdenite is either restricted to the potassic and chlorite-sericite alteration zones of the ore-bearing granite as fine disseminations or alternatively as veinlet infills within the propylitic halos. The molybdenite occurrences along with pyrite, chalcopyrite, galena, and tennantite dissemination are assigned to the primary ore stage, while the NNE–SSW to N–S ore-bearing system is related to the secondary ore stage. It consists of pyrite, chalcopyrite, bornite, covellite, diagenite, sphalerite, hematite, galena, gold, and chenguodaite. The predominance of cockade and crack-and-seal textures suggest multiple episodes of ore-forming fluid circulations under epithermal conditions. The supergene stage is achieved by subordinate malachite, azurite, barite, hematite, epsomite, and chrysocolla. From the descriptions above, we argue that the Imourkhssen Cu±Mo±Au±Ag mineralization shares many mineralogical and paragenetic attributes of porphyry-copper deposits.

The geodynamic evolution of the Anti-Atlas belt post-Pan-African orogeny (~650 Ma) remains debated, particularly regarding the basement beneath the Central Anti-Atlas, and the geological processes leading to the formation of the Ediacaran Saghro Group (SG), and Ouarzazate Group (OG). New LA-ICP-MS U-Pb ages of 575 ± 3 Ma and 564 ± 2 Ma were obtained respectively from samples Zg-106, and Zg-119 from the OG. In addition, detrital zircons from SG sediments yield a prominent 2.1 Ga age peak, indicating local recycling of Paleoproterozoic basement material. Geochemically, two magmatic series are identified : (i) a SG mafic-intermediate calc-alkaline series with Nb-Ta and Ti negative anomalies from early back-arc basin setting; and (ii) a felsic-intermediate high-K calc-alkaline to shoshonitic series of the OG, exhibiting continental magmatic arc signatures. Isotope data (εNd (t): +3.2 to +4.5, TDM = 1431 − 1197 Ma for SG; εNd (t): −0.9 to +1.1, TDM = 1526− 1252 Ma for OG), indicates that the SG formed from a dominantly juvenile, mantle-derived source, with limited crustal contribution; while the slightly younger OG involved significant reworking of older, evolved continental crustal material. These findings sustain a model where Early Ediacaran SG sediments and associated mafic-intermediate volcanics were formed in a back-arc basin. During this basin development, its shoulders were locally formed by the 2.1 Ga Paleoproterozoic basement, supplying Paleoproterozoic zircons to the Saghro host basin. This, further supports the occurrence of the Eburnian basement north of the Anti-Atlas Major Fault (AAMF). Additionally, the younger OG reflects a Late Ediacaran continental crust collapse event involving widespread crustal reworking and the emplacement of a Silicic Large Igneous Province (SLIP).

The geodynamic evolution of the Anti-Atlas belt post-Pan-African orogeny (~650 Ma) remains debated, particularly regarding the basement beneath the Central Anti-Atlas, and the geological processes leading to the formation of the Ediacaran Saghro Group (SG), and Ouarzazate Group (OG). New LA-ICP-MS U-Pb ages of 575 ± 3 Ma and 564 ± 2 Ma were obtained respectively from samples Zg-106, and Zg-119 from the OG. In addition, detrital zircons from SG sediments yield a prominent 2.1 Ga age peak, indicating local recycling of Paleoproterozoic basement material. Geochemically, two magmatic series are identified : (i) a SG mafic-intermediate calc-alkaline series with Nb-Ta and Ti negative anomalies from early back-arc basin setting; and (ii) a felsic-intermediate high-K calc-alkaline to shoshonitic series of the OG, exhibiting continental magmatic arc signatures. Isotope data (εNd (t): +3.2 to +4.5, TDM = 1431 − 1197 Ma for SG; εNd (t): −0.9 to +1.1, TDM = 1526− 1252 Ma for OG), indicates that the SG formed from a dominantly juvenile, mantle-derived source, with limited crustal contribution; while the slightly younger OG involved significant reworking of older, evolved continental crustal material. These findings sustain a model where Early Ediacaran SG sediments and associated mafic-intermediate volcanics were formed in a back-arc basin. During this basin development, its shoulders were locally formed by the 2.1 Ga Paleoproterozoic basement, supplying Paleoproterozoic zircons to the Saghro host basin. This, further supports the occurrence of the Eburnian basement north of the Anti-Atlas Major Fault (AAMF). Additionally, the younger OG reflects a Late Ediacaran continental crust collapse event involving widespread crustal reworking and the emplacement of a Silicic Large Igneous Province (SLIP).

The geodynamic evolution of the Anti-Atlas belt post-Pan-African orogeny (~650 Ma) remains debated, particularly regarding the basement beneath the Central Anti-Atlas, and the geological processes leading to the formation of the Ediacaran Saghro Group (SG), and Ouarzazate Group (OG). New LA-ICP-MS U-Pb ages of 575 ± 3 Ma and 564 ± 2 Ma were obtained respectively from samples Zg-106, and Zg-119 from the OG. In addition, detrital zircons from SG sediments yield a prominent 2.1 Ga age peak, indicating local recycling of Paleoproterozoic basement material. Geochemically, two magmatic series are identified : (i) a SG mafic-intermediate calc-alkaline series with Nb-Ta and Ti negative anomalies from early back-arc basin setting; and (ii) a felsic-intermediate high-K calc-alkaline to shoshonitic series of the OG, exhibiting continental magmatic arc signatures. Isotope data (εNd (t): +3.2 to +4.5, TDM = 1431 − 1197 Ma for SG; εNd (t): −0.9 to +1.1, TDM = 1526− 1252 Ma for OG), indicates that the SG formed from a dominantly juvenile, mantle-derived source, with limited crustal contribution; while the slightly younger OG involved significant reworking of older, evolved continental crustal material. These findings sustain a model where Early Ediacaran SG sediments and associated mafic-intermediate volcanics were formed in a back-arc basin. During this basin development, its shoulders were locally formed by the 2.1 Ga Paleoproterozoic basement, supplying Paleoproterozoic zircons to the Saghro host basin. This, further supports the occurrence of the Eburnian basement north of the Anti-Atlas Major Fault (AAMF). Additionally, the younger OG reflects a Late Ediacaran continental crust collapse event involving widespread crustal reworking and the emplacement of a Silicic Large Igneous Province (SLIP).

The geodynamic evolution of the Anti-Atlas belt post-Pan-African orogeny (~650 Ma) remains debated, particularly regarding the basement beneath the Central Anti-Atlas, and the geological processes leading to the formation of the Ediacaran Saghro Group (SG), and Ouarzazate Group (OG). New LA-ICP-MS U-Pb ages of 575 ± 3 Ma and 564 ± 2 Ma were obtained respectively from samples Zg-106, and Zg-119 from the OG. In addition, detrital zircons from SG sediments yield a prominent 2.1 Ga age peak, indicating local recycling of Paleoproterozoic basement material. Geochemically, two magmatic series are identified : (i) a SG mafic-intermediate calc-alkaline series with Nb-Ta and Ti negative anomalies from early back-arc basin setting; and (ii) a felsic-intermediate high-K calc-alkaline to shoshonitic series of the OG, exhibiting continental magmatic arc signatures. Isotope data (εNd (t): +3.2 to +4.5, TDM = 1431 − 1197 Ma for SG; εNd (t): −0.9 to +1.1, TDM = 1526− 1252 Ma for OG), indicates that the SG formed from a dominantly juvenile, mantle-derived source, with limited crustal contribution; while the slightly younger OG involved significant reworking of older, evolved continental crustal material. These findings sustain a model where Early Ediacaran SG sediments and associated mafic-intermediate volcanics were formed in a back-arc basin. During this basin development, its shoulders were locally formed by the 2.1 Ga Paleoproterozoic basement, supplying Paleoproterozoic zircons to the Saghro host basin. This, further supports the occurrence of the Eburnian basement north of the Anti-Atlas Major Fault (AAMF). Additionally, the younger OG reflects a Late Ediacaran continental crust collapse event involving widespread crustal reworking and the emplacement of a Silicic Large Igneous Province (SLIP).