Plombotectonique des gisements du Maroc

Abstract

The synthesis of 240 lead isotopes analyzes, measured on Moroccan ore deposits of Ediacarian to Neogene ages located in all geotectonic domains of Morocco allows a global reflection on the metallogeny of Morocco. The isotopic compositions vary widely, from 17.738 (Bou Skour) to 18.905 (Draa Sfar) for the 206Pb/204Pb ratio, and from 15.521 to 15.706 for the 207Pb/204Pb ratio. The source of lead in the studied deposits is located in the upper continental crust, except for those in the Anti-Atlas (Bou Skour, Imiter, etc.) and some in the High Atlas (Azegour) with a clear mantellic contribution. Isotopic variations noted at the scale of a district result either from the presence of several superimposed hydrothermal events calling upon different local sources as at Tighza, or from a single event disturbed by the segmentation of a volcanosedimentary basin, as for the Jebilet and Guemassa ore deposits. At the scale of the deposit (Draa Sfar, Bou Skour), isotopic variations result from the superposition of several hydrothermal events each with their own lead and associated metals. Overall, we can distinguish three generations of lead incorporated successively into the Moroccan geological base by magmatism and / or hydrothermalism, characterized by their 206Pb/204Pb ratios: 17.74-17.90 (Ediacarian), 18.10-18.40 (Hercynian) and 18.75-18.90 (Alpine). Ediacarian lead is present in the Anti-Atlas, and very locally in the meseta (Bouznika), and feeds in part on the mafic magmatism of Gondwana. Hercynian lead is the most represented and displays a definitive rupture in the source of metals, which is now exclusively crustal. It invades all Moroccan areas, including the Anti-Atlas, where it re-mobilizes and mixes with the Ediacaran lead. Alpine lead, more discreet, marks out the large scarf going from Agadir to Nador which traces on the surface the mantle plume of the Canaries and accompanies a Neogene magmatism which may also have acted as a simple engine remobilizing Hercynian lead, in particular to form MVT deposits from Touissit. The Hercynian and Alpine lead influxes are partly responsible for resetting the mineralizations, as at Bou Azzer or Imiter. In the Sawkins’s model, lead isotopic results support successive remobilisations of lead stored in primary and secondary tanks, as well as inheritance phenomena. Finally, the good transfer of the isotopic signature of lead from deposits to surface gossans shows that the isotopic geochemistry of lead is a useful tool for mineral exploration in Morocco.

Multiscale Structural Analysis of Ediacaran–Cambrian Rocks on the Northeastern Edge of the Saghro Inlier (Eastern Anti-Atlas): Relevance of Post-Cambrian Deformation

“…The Anti-Atlas Mountains are believed to have evolved during a long geological history, resulting from different orogenies, including the Eburnean and Panafrican during Precambrian time, and then the Variscan and Atlasic during the Phanerozoic (Figure 9). Such a tectono-thermal telescoped evolution caused polycyclic hydrothermalism that would explain the complicity and diversity of ore deposits in the Anti-Atlas belt [43,48,49]. During the Phanerozoic time, several tectono-magmatic and hydrothermal events have been recorded on the Anti-Atlas belt.…”

Metallogeny and Genesis of Fault-Filling Barite-Sulfide Veins (Ougnat, Morocco): Petrography, Fluid Inclusion, and Sr-S Isotopic Constraints

“…Barite holds significant value in industries such as aerospace, chemicals, and petroleum, as well as for the production of white goods [1][2][3][4][5][6][7][8][9][10][11]. Thanks to its versatility in these fields of However, despite this obvious economic importance, the study of barite deposits genesis in Morocco remains very limited [12][13][14][15][16][17][18][19][20][21]. Barite deposits are widely distributed over the whole Moroccan territory, hosted in various geological formations of varying nature and age [14,22].…”

“…Barite deposits are widely distributed over the whole Moroccan territory, hosted in various geological formations of varying nature and age [14,22]. Three main types of barite deposits have been studied in Morocco, based on their shape of mineralization (stratiform, karstic, and vein deposits) [14,16,22,23] (Figure 1). Stratiform mineralization is rare and limited, and can only be seen embedded within the Lower Paleozoic formations of the High Atlas [16].…”

“…Three main types of barite deposits have been studied in Morocco, based on their shape of mineralization (stratiform, karstic, and vein deposits) [14,16,22,23] (Figure 1). Stratiform mineralization is rare and limited, and can only be seen embedded within the Lower Paleozoic formations of the High Atlas [16]. Karstic mineralization is exploited in the western Paleozoic Meseta, notably at the Jebel Irhoud mine [20,22] and Bou Ouzel mine [15].…”

Assessment of a Mining-Waste Dump of Galena Mine in the East of Morocco for Possible Use in Civil Engineering

“…1B) (Hudson-Edwards et al, 2015). The Touissit-Bou Beker district is the Mississippi Valley-type deposits, it is embedded in a thick sequence of dolomitized rocks by hydrothermal activities around 170 Ma, belonging to the Jurassic carbonate platform (Wadjinny, 1998, Bouabdellah, 2009, Marcoux et al, 2021. It comprises a Paleozoic basement consisting of metamorphites, granodiorites and rhyodacites and a tabular Mesocenozoic cover with calcareous Jurassic facies, a shallow calcarodolomitic layer of Aalenian-Bajocian age (Hauts Plateaux Slab), and by marly and detrital sediments of the Upper Jurassic (Fig.…”