Geological and Geochemical Assessment of Precious Metal Mineralization in the Jbel Houanite Region (Eastern High Atlas, Morocco): Implications for Resource and Environmental Management
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1
Applied Geosciences Laboratory, Department of Geology, Faculty of Sciences, Mohammed First University, P.O. Box 717, 60000 Oujda, Morocco
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Geo-Biodiversity and Natural Patrimony Laboratory, Scientific Institute, Mohammed-V University of Rabat, Avenue Ibn Batouta, Agdal, PO Box 703, 10106, Rabat-City, Morocco.
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Geophysics and Natural Hazards Laboratory, Department of Geomorphology and Geomatics (D2G), Scientific Institute, Mohammed-V University in Rabat, Avenue Ibn Batouta, Agdal, PO Box 703, 10106, Rabat-City, Morocco
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Geoscience Laboratory, Department of Geology, Faculty of Science, Ibn Tofail University, B.P. 133, Kenitra 14000, Morocco
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Applied Chemistry, Geomines and Modeling, Polidisciplinary Faculty of Ouarzazate, Ibn Zohr University, Ouarzazate, Morocco.
Corresponding author
Amine Talih
Geo-Biodiversity and Natural Patrimony Laboratory, Scientific Institute, Mohammed-V University of Rabat, Avenue Ibn Batouta, Agdal, PO Box 703, 10106, Rabat-City, Morocco.
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ABSTRACT
Located within the Eastern High Atlas Mountain Range of Morocco, the Jbel Houanite mining district represents a polymetallic hydrothermal system with a structure-controlled genetic origin associated with a Paleozoic tectonic heritage followed by Atlasic reactivation. The results of the litho-structural studies suggest that there is strong preferential localization of mineralization along E-W and NE-SW fault systems and sub-vertical foliation developed due to inherited Hercynian shear zones. The occurrence of quartz stockwork veins and extensive fracturing would suggest that there has been prolonged hydrothermal circulation through these structural corridors, which were subject to high permeability. Geochemical data also show a clear segregation in metallurgy between a Fe-Zn sulfide assemblage typical of a volcano-sedimentary environment, and another related to an Au-Sb-Ag-Pb hydrothermal event linked to tectonic remobilization. Antimony was found to be the most reliable indicator element for gold mineralization. The hydrothermal alteration of the rocks is dominated by phyllitic assemblages that show enrichment in K-Rb-Cs and depletion in Ca; this reflects intense sericitization associated with fluid movement along deformation zones. The presence of Ag/Au ratios indicates that the prevailing conditions were mesothermal to epithermal, and associated with intermediate depth hydrothermal activity within the crust. Analyses conducted for mineralogical maps and elemental traces show that Au, As, Fe and Sb are strongly spatially associated with each other; with arsenopyrite and stibnite occurring among the principal As- and Sb-bearing sulfide phases associated with the Au-bearing mineralized zones. Geochemical indications of porphyry, volcanogenic massive sulphides (VMS); and Ni-Cu have not been found and thus exclude a direct magmatic or submarine volcanogenic origin, thereby supporting the idea that the mineralization occurred in a tectonically driven orogenic setting. The suite of structural, mineralogical, and geochemical evidence collected indicates that there has been a polygenic process involved with the mineralization first depositing as an early syngenetic sulphide phase, followed by tectonically driven hydrothermal movement of Au and concentration of Au within shear zones. There are also geological similarities between the Jbel Houanite mining district and major orogenic gold provinces within N. Africa, and indicate how important inherited crustal structures are in determining the circulation of fluids and their mineralization.