Metallogenesis of the Cu-Ni sulfide type mineralization in the Bounhas vein deposit (Eastern Anti-Atlas, Morocco): Insights from ore mineral paragenesis and fluid phases

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

“…Field-based studies were conducted to establish the relationships among the mineralized vein field, the host rock, and their structures during the precipitation of barite mineralization. Barite samples were collected for petrographic studies (thirty samples), coupled Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray analysis (EDX) (ten samples), strontium and sulfur isotopic analysis (five samples for both 87 Sr/ 86 Sr and δ 34 S, respectively), and microthermometric studies of fluid inclusions (50 measurements). SEM combined with EDX enabled us to (i) examine the texture and microscopic structure of the samples after carbon metallization and (ii) perform surface microanalysis and qualitative multi-elemental analysis [81].…”

“…(iii) Banded texture is sparsely developed throughout the Massif, displaying palmate layers of white and pink barite associated with iron and manganese oxides to form alternating bands (Figure 5e). Generally, banded textures indicate a context of intermittent and slow opening of mineralized veins [86,87], in an extensional tectonic environment. (iv) Crested texture extends in several locations along the mineralized structures, consisting of gathered flattened tabular crystal facets (Figure 5f).…”

“…The 87 Sr/ 86 Sr ratio fractionates either below 400 • C or during hydrothermal crystallization or dissolution. Additionally, the parent of 87 Sr, namely 87 Rb, generally does not incorporate into the crystal lattice of barite [116]; thus, the strontium composition of barite remains relatively constant over time. In the Ougnat Massif, measurements revealed a moderate to high 87 Sr/ 86 Sr ratio (ranging from 0.710772 to 0.710816) (Figure 9b).…”

“…Additionally, the parent of 87 Sr, namely 87 Rb, generally does not incorporate into the crystal lattice of barite [116]; thus, the strontium composition of barite remains relatively constant over time. In the Ougnat Massif, measurements revealed a moderate to high 87 Sr/ 86 Sr ratio (ranging from 0.710772 to 0.710816) (Figure 9b). These values lie between the radiogenic isotopic compositions of strontium in the mineralization deposit by hydrothermal solutions interacting with crustal brine [114] and the non-radiogenic isotopic signature of seawater from the Triassic to Jurassic periods [19].…”

“…Furthermore, Ref. [103] proposed that elevated 87 Sr/ 86 Sr isotopic ratios (>0.707) are characteristic of crustal brines derived from the basement, while lower 87 Sr/ 86 Sr ratios (<0.707) correspond to fluids derived from sedimentary cover. In summary, isotopic analyses of strontium in barite provide valuable information on the origin and evolution of fluids involved in hydrothermal processes, shedding light on the geological conditions that led to these deposits.…”