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Abstract The Imiter inlier at the eastern Anti-Atlas chain (Morocco) hosts a world-class epithermal Ag-Hg deposit, and several occurrences of sulfide-magnetite mineralization. These occurrences are confined to transcurrent faults that cut mildly to highly potassic I- and S-type granite intrusions (e.g., Igoudrane, Bou Teglimt, Taouzzakt and Bou Fliou). In this contribution, we present new field, petrographic and microanalytical data of the Bou Fliou sulfide-magnetite mineralization in the northwestern part of the Bou Teglimt granodiorite intrusion (567 ± 6Ma). Field and microscopic investigations reveal pervasive silicification and potassic alteration associated with iron oxides-rich (>10 vol %) veins, stockworks, and breccias along NE-SW faults. The ore minerals are mainly magnetite, hematite, chalcopyrite, pyrite, sphalerite, Ag-galena, cobaltite, and less abundant Bi-sulfosalts (i.e., cosalite, galenobistmuthite, and llilanite-gustavite). The low-titanium iron oxides (magnetite and hematite), widespread iron-rich breccia, association with crustal scale fault zone, pervasive alteration, and overprinting mineral assemblages suggest a shallow level IOCG-style mineralization. High-order splays of the major fault zone could have provided effective traps for magmatic and basinal Cu and Zn-Pb hydrothermal fluids. The ∼550 Ma intrusive phases in the region could have contributed by fluid, elements or heat in a local effective blumbing. The mineralogical and ore textural criteria reflecting ore formation at a realtively shallow crustal environment, but a fluid inclusion study is needed to characterize the ore fluids and mechanism of ore deposition. [ABSTRACT FROM AUTHOR]

For over 50 years the Pan African orogeny has been recognized as a Neoproterozoic tectonothermal episode affecting West Africa 800–550 Ma. As such, the Pan African events are similar to the Appalachian orogenic cycle extending from ∼1100 to 250 Ma and the Cordilleran orogenic cycle of 350 Ma to the present. A significant difference is that the Appalachian orogenic cycle has long been recognized as consisting of separate Grenville, Taconic, Acadian and Alleghenian orogenies. Similarly, the Cordilleran orogenic cycle consists of distinct Antler, Sonoma, Nevadan, Sevier, Laramide and ongoing Cascadian-Andean orogenies. Failure to distinguish individual tectonic events in the Anti-Atlas Mountains has been attributable to the dearth of radiometric dates in this region. Since 2000, precision geochronologic dating in the Anti-Atlas Mountains, Morocco, has provided a means by which it is now appropriate to designate a Pan African orogenic cycle consisting of separate distinct orogenic events. We herein propose the following distinct orogenic events in the Anti-Atlas Mountains of Morocco: Iriri-Tichibanine orogeny (760–700 Ma), Bou Azzer orogeny (680–640 Ma) and the WACadomian orogeny (620–555 Ma). [ABSTRACT FROM AUTHOR]

The Central High Atlas is distinguished by map-scale, sigmoid, and narrow magmatic-cored ridges, which separate wide and open synclines. The origin of these structures has been debated for years. This study addresses this issue from a paleostress perspective, using mesostructural analysis in the Imilchil region and incorporating insights from previous research. Our analysis reveals that the Central High Atlas ridges developed through two main structural stages from the Jurassic to the Cenozoic. The first stage involved an extensional event characterized by NW-SE-oriented σ3, coeval with the Early Jurassic Tethyan extension. This was followed by wrench tectonics driven by oblique left-lateral motion of Africa with respect to Europe. This events is marked within the Central High Atlas by ENE-WSW-oriented σ1 and NNW-SSE-oriented σ3. The basin-scale left-lateral motion likely drove the formation of sigmoid stepovers, facilitating the emplacement of magmatic bodies from the Middle Jurassic to the Early Cretaceous. The second deformation stage is likely associated with the convergence between Africa and Europe and the consecutive Alpine orogeny. In the study area, this stage consists of three events: a pre-folding strike-slip event with NNE-SSW to N–S-oriented σ1, and a pre-folding strike-slip event with NW-SE-oriented σ1. Near the diapirs, the analyzed mesostructures display syn-to post-folding patterns in some locations, indicating pre-Alpine layer tilting driven by salt tectonics. The final event is marked by significant post-folding NW-SE compression, associated with the Central High Atlas basin inversion and the compaction of pre-existing magmatic-cored salt diapirs. This study highlights the complex deformation history that has influenced the evolution of the Central High Atlas ridges and provides evidence of the significant role of strike-slip tectonics during the post-rift period and magmatic emplacement, as well as in the early phases of basin inversion. [ABSTRACT FROM AUTHOR]

The concept of cyclic closure and opening of oceans along the same crustal scar was introduced by J.T. Wilson (1966) based on the example of the Atlantic Ocean and its continental borders. At that time, the only Variscan orogen cited south of Europe along the Atlantic coast of Africa was the Mauritanides of Mauritania. Here we report on the recent achievements in the Mauritanides from Mauritania to Morocco, and on the Moroccan Meseta orogen, which also records the Variscan orogeny. The Southern and Central Mauritanides are a poly-orogenic, Pan-African and Variscan orogen characterized by a thin-skinned tectonic style that mirrors the structure of the southern Appalachians, but with a different tectonic history. The Northern Mauritanides crops out in the Moroccan Oulad Dlim massif, northwest of the Reguibat Rise. This part of the belt compares with the southern part, but additionally exhibits in the west a Silurian-Devonian sector that shows possible affinities with Gondwana-derived Appalachian terranes. The Western Meseta is only affected by Variscan events, which were mild in the westernmost Meseta Coastal Block, while the Eastern Meseta was also affected by Eo-Variscan events. The along-strike change from the Mauritanides to the Meseta orogen is interpreted as a transition from a head-on collision south of the South Meseta transform fault (SMF, precursor of the South Atlas Fault, SAF) to a dextral, transpressional collision north of the SMF. South of the SAF, the Anti-Atlas and the Dhlou-Zemmour expose the foreland foldbelts of the Meseta and northernmost Mauritanides. The Coastal Block was likely displaced from the south-westernmost Anti-Atlas during the Early Carboniferous. The Wilson Cycle concept mostly applied in that the Atlantic Ocean opened where the prior Rheic Ocean had closed. Possible exceptions are the Sehoul Block north of Western Meseta and the Silurian-Devonian Sector of the Oulad Dlim massif, which may have separated from NW-Africa and re-amalgamated to it during the Variscan orogeny. Likewise, a NW-African fragment from the Anti-Atlas may have stranded in offshore Massachusetts in eastern North America. An early Ediacaran-Cambrian Wilson cycle nested in the classic cycle introduced by Wilson (1966) occurred along the margin of NW-Africa, where Cadomian terranes rifted off Africa, and some were transferred to Europe and some accreted back to NW-Africa. This early cycle likely controlled the localization of the subsequent Rheic rift, and that of the Atlantic rift along the Mauritanides after the Variscan collision. • Crucial legacy of NW-Africa geology to the Rodinia-to-Pangea Wilson Cycle. • Comprehensive review of the Variscan orogens along the NW African margin. • Western extension of the South Meseta-Atlas Fault at the latitude of SE New England. • This transform fault possibly separated domains with opposing subduction polarity. • The Cadomian cycle nested at the beginnings of the reference cycle influenced it. [ABSTRACT FROM AUTHOR]

Abstract This study presents new U–Pb zircon ages for three granitoid bodies in the Imiter inlier at the eastern part of the Moroccan Anti-Atlas chain, which is located in the northwestern edge of the West African Craton (WAC). Analyzes of zircon grains yield the following ages: 538 ± 6 and 575 ± 10 Ma for the Igoudrane massif, 567 ± 6 Ma for the nearby Bou Teglimt granodiorite, and 582 ± 6 Ma for the Bou Fliou granite. These new data reveal that the Igoudrane massif is younger than previously thought (677 Ma), and that all the granitoids in the Imiter area are Ediacaran in age and are related to the Ouarzazate Group. Sm-Nd isotopic data yield negative εNd(t) values (−4.5 to −0.2) and T DM model ages of 1.04–1.82 Ga. These data indicate the presence of an inherited Paleoproterozoic to Archaean component in some zircon grains and show that generation of the parent magmas involved a Neoproterozoic juvenile contribution and recycling of an older crustal component. These new data allow reinterpreting the geochemical and isotopic data of the granitoids, and revisiting the structural significance to the Igoudrane massif, which was assumed until now to be coeval with the major Pan-African event of the Central Anti-Atlas. They also bring significant constraints to discuss the context and age of deposition of the Saghro Group, which is still a matter of debate. All these data provide evidence of an emplacement of the Imiter granitoids in a subduction complex, which affected all of the Anti-Atlas chain during the Late Proterozoic time. Highlights • We provide new zircon ages for the granitoids of the Imiter inlier (Saghro, Eastern Anti-Atlas). • The crystallization age of the Igoudrane massif (575 ± 10 Ma) is younger than previously thought. • The granitoids in the Imiter inlier are Ediacaran to Lower Cambrian in age (538–582 Ma). • An Archaean to Paleoproterozoic basement is present under the Eastern Anti-Atlas. [ABSTRACT FROM AUTHOR]

This report is dedicated to the Sidi Bou Othmane limestones outcrops, which are exposed in the Central Jebilet. This area experienced strong Hercynian metamorphism and deformation. Strongly metamorphosed and recrystallized conodonts point to Frasnian-Famennian ages, which are reported from this region for the first time. Based on conodont data, we thus revise the age of the Sidi Bou Othmane limestones, which are definitely Late Devonian in age instead of Mississippian (late Viséan) as reported in previous publications. Six stratigraphic intervals from the Middle falsiovalis to marginifera utahensis Zones are identified. The colour alteration index of conodonts (CAI) is very high and varies from CAI 6 to CAI 8, indicating a thermal gradient from 360 °C to over 600 °C for the conodont bearing strata, which is consistent with the isograds obtained in previous publications. Transgressive Upper Devonian limestones discontinuously overlie Ordovician psammites, beginning with a variably thick polymict conglomerate. This unconformity provides evidence of a regional exhumation and erosional event of the Ordovician strata in the Central Jebilet, prior to Upper Devonian transgression. Together with the Koudiat Laabid limestones at Jebel Gueliz in the south, these Upper Devonian outcrops, locally covered by upper Viséan Sarhlef Schists, suggest that the upper Viséan basin of Central Jebilet was divided in a N –S elongated paleogeographical highland formed by the Ordovician and Devonian bedrock. The proposed paleogeographic configuration could explain the lithological differences between the slate deposits to the west and the flysch-like deposits to the east. The exhumation/erosion of Ordovician strata in the Sidi Bou Othmane area may be related to the Eovariscan block faulting and the preorogenic extension of the Meseta domain. • Frasnian to Famennian metamorphosed conodonts discovered from outcrops inferred to upper Visean in Sidi Bou Othmane area. • Regional exhumation and erosion of the Ordovician substratum occurred prior to the Upper Devonian transgression. • N –S paleogeographical highland separates the Sarhlef Schists and the Kharrouba Flysh. • Upper Devonian carbonate platform from Eastern to Central Jebilet covered by upper Visean deposits. [ABSTRACT FROM AUTHOR]

Located along the northwestern edge of the West African Craton, Morocco exhibits a wide variety of magmatic events from Archean to Quaternary. The oldest magmatic rocks belong to the Archean Reguibat Shield outcrops in the Moroccan Sahara. Paleoproterozoic magmatism, known as the Anti-Atlas granitoids, is related to the Eburnean orogeny and initial cratonization of the WAC. Mesoproterozoic magmatism is represented by a small number of mafic dykes known henceforth as the Taghdout mafic volcanism. Massive Neoproterozoic magmatic activity, related to the Pan-African cycle, consists of rift-related Tonian magmatism associated with the Rodinia breakup, an Early Cryogenian convergent margin event (760–700 Ma), syn-collisional Bou-Azzer magmatism (680–640 Ma), followed by widespread Ediacaran magmatism (620–555 Ma). Each magmatic episode corresponded to a different geodynamic environment and produced different types of magma. Phanerozoic magmatism began with Early Cambrian basaltic (rift?) volcanism, which persisted during the Middle Cambrian, and into the Early Ordovician. This was succeeded by massive Late Devonian and Carboniferous, pre-Variscan tholeiitic and calc-alkaline (Central Morocco) volcanic flows in basins of the Moroccan Meseta. North of the Atlas Paleozoic Transform Zone, the Late Carboniferous Variscan event was accompanied by the emplacement of 330–300 Ma calc-alkaline granitoids in upper crustal shear zones. Post-Variscan alkaline magmatism was associated with the opening of the Permian basins. Mesozoic magmatism began with the huge volumes of magma emplaced around 200 Ma in the Central Atlantic Magmatic Province (CAMP) which was associated with the fragmentation of Pangea and the subsequent rifting of Central Atlantic. CAMP volcanism occurs in all structural domains of Morocco, from the Anti-Atlas to the External Rif domain with a peak activity around 199 Ma. A second Mesozoic magmatic event is represented by mafic lava flows and gabbroic intrusions in the Internal Maghrebian flysch nappes as well as in the external Mesorif. This event consists of Middle-Upper Jurassic MORB tholeiites emplaced during opening of the Alpine Tethys ocean. The Central High Atlas also records Early Cretaceous alpine Tethys magmatism associated with the aborted Atlas rift, or perhaps linked to plume activity on the edge of the WAC. Cenozoic magmatism is associated with Tertiary and Quaternary circum-Mediterranean alkaline provinces, and is characterized by an intermittent activity over 50 Ma from the Anti-Atlas to the Rif Mountain along a SW–NE volcanic lineament which underlines a thinned continental lithosphere. [ABSTRACT FROM AUTHOR]

The Imiter inlier (eastern part of the Moroccan Anti-Atlas) is located on the northwestern border of the West African Craton (WAC) and exhibits a range of Pan-African granitoids. Three massifs that crosscut the Imiter Saghro Group were targeted in this work: the Igoudrane granodiorite, Bou Teglimt granodiorite and Bou Fliou granite. We present here additional geochemical analyses (major and trace elements) and Sm-Nd isotopic data, which define two distinct groups: (i) the Igoudrane massif (677 Ma) and (ii) the Bou Teglimt granodiorite (576 Ma) and the Bou Fliou granite (550 Ma). Geochemical data confirm the calc-alkaline signature of the studied granitoids. Both groups of granitoids are slightly peraluminous and show strong negative anomalies in Nb, Ta and Ti in multi-element plots normalized to the primitive mantle. The granitoids have low 143 Nd/ 144 Nd initial ratios (0.5116–0.5117), with T DM model ages ranging from 1.73 to 1.52Ga. The εNd (t) values are negative, decreasing from the Igoudrane samples (−1.1 to −3.1) to the Bou Teglimt granodiorite (−3.0 to −3.3) and Bou Fliou (−4.2 to −4.8). All these data suggest a mixed magmatic origin involving a juvenile mantle source and an old, at least Paleoproterozoic crust. Given Mesoproterozoic rocks are lacking or very scarce in the Anti-Atlas, these results confirm the existence of an old cratonic basement beneath the eastern Anti-Atlas, and therefore suggest that the northern border of the West African Craton must be placed further to the north, as suggested by previous work in this region. [ABSTRACT FROM AUTHOR]

The northern margin of the West African Craton is characterized by Paleoproterozoic siliciclastic sediments intruded by ca. 2.1-2.0 Ga Eburnean granitoids. New geochronological data highlight the occurrence of a Rhyacian (2.10 Ga) tonalitic to trondhjemitic magmatic suite, followed by an Orosirian (2.040-2.035 Ga) magmatic suite composed of coeval calc-alkaline diorites, mesocratic granites and leucogranites. Whole-rock major and trace element compositions indicate that: (i) the Rhyacian tonalites and trondhjemites suggest a subduction environment, an island-arc arc or an active continental margin; (ii) the Orosirian plutonic rocks show a geochemical heterogeneity; (iii) the chemical features of diorites correspond to calc-alkaline M-type suites; (iv) granodiorites and granites are typical calc-alkaline I-type granitoids, and (iv) leucogranites, with peraluminous composition, reflect a crustal melting. While the Rhyacian magmatic event indicates a subduction environment, the Orosirian magmatic event is more complex, and the geochemical signatures imply involvement of mantellic magmas and crustal melting. The contemporaneity of these Orosirian magmatic suites and their siliciclastic sedimentary host-rocks suggest a back-arc geodynamic context, similar to what was described in the Reguibat Rise, Mauritania. • Rhyacian tonalites and trondhjemites, followed by Orosirian diorites and granites. • Orosirian calc-alkaline M-type diorites, I-type granitoids, and leucogranites. • Orosirian back-arc geodynamic context similar to that described in the Reguibat Rise [ABSTRACT FROM AUTHOR]

From the Neoproterozoic to Cenozoic, different extensional and transpressional tectonics events occurred during the Pan-African, Variscan and Alpine orogenic cycles in the Precambrian and Paleozoic terrains of the Saghro Massif of the eastern Anti-Atlas, Morocco. This makes it a key zone to investigate fault distribution and basement-cover interactions. The present research aims to elaborate a detailed fracturation map and the structural interpretation of the Precambrian and Paleozoic outcrops in the northeastern part of the Saghro Massif. Sentinel-2A and Landsat-8 Oli images were used in conjunction with Digital Elevation Model (DEM). The remote sensing study was completed by an integrated interpretation including structural data from existing geological maps and our field investigations. The results show four fault systems, namely N–S to NNE-SSW, NE-SW to ENE-WSW, ENE to E-W, and NW-SE to WNW-ESE. Faults and folds geometry in the Paleozoic and Mezo-Cenozoic terrains were controlled by the reactivation of inherited basement structures such as faults and alternate competent and incompetent formations. The major mechanical discontinuities between Precambrian, Paleozoic and Mesozoic-Cenozoic terrains restrain the propagation of fractures from top to bottom during the Variscan and Atlasic orogenesis. The structural map established in this work helps to improve significantly the existing geological maps and to understand the architecture of the High Atlas foreland and overprinting relationships in the Saghro polytectonic massif. • Integrating remote sensing and geological data to faults mapping in the basement-cover context. • Characterizing the faults distribution in the Saghro polytectonic massif. • Understanding the architecture of the High Atlas foreland and overprinting relationships in the Saghro polytectonic massif. • Fractures controls on mineralization distribution in the Precambrian and Paleozoic Saghro massif. [ABSTRACT FROM AUTHOR]