THE GENESIS OF THE TIGRININE-TAABEST MVT PB-ZN ORE DEPOSIT IN CENTAL HIGH ATLAS: CONSTRAINTS FROM FLUID INCLUSION AND C-O-S-PB ISOTOPES STUDIES
The δ34S values range from 6.6 to 9.4‰ and from 12.7 to 13.0‰ for galena and sphalerite respectively with an average δ34Sfluid of 13‰. Sulfur derived most likely from Triassic sulfates through thermochemical-sulfate reduction. Galena samples have a homogeneous Pb composition with 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios ranging from 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios ranging from 18.229 to 18.236, 15.643 to 15.655, and 38.448 to 38.527 respectively. This Pb composition plots in the upper crust and the orogene and suggest well-mixed source rocks of metals.
During the African-European continental collision (Alpine orogeny), the metal-bearing fluids were remobilized and migrated through major E-W to NE-SW- trending faults. Mixing of the hot, ore-bearing fluids with a cooler fluid are likely the main cause of ore precipitation as indicated by C-O isotopes and fluid inclusions data.