Fluid inclusion microthermometry and rare earth element distribution in the celestites of the Jebel Doghra ore deposit (Dome Zone, northern Tunisia): towards a new genetic model

International audienceThe celestite ore of Jebel Doghra Occurs as stratabound deposits within the cap-rock of a diapiric structure of Triassic salt-rocks. The celestite deposits result mainly from the late diagenetic to epigenetic replacement of the carbonated host-rocks giving rise to a dolomite-celestite "banded ore". Celestite is locally observed within fractures. This Study proposes a new genetic model based on fluid inclusion (F1) microthermometry and REE geochemistry. FI show that celestite, Occurring either as stratabound bodies or locies, was deposited from a highly saline (20.7 +/- 1.3 wt% NaCl equivalents) and warm (174 +/- 3 degrees C) basinal fluid, which contains hydrocarbon droplets and CO2. The geochemistry of the REE shows that the deposition of celestite is clue to the mixing between a deep-sourced fluid which has acquired high Sr concentrations by leaching feldspar-rich series in depth and a sulfate-rich solution associated with the Triassic evaporites