Mobilisation of rare earth elements in shear zones: Insights from the Tabouchent granodioritic pluton (Jebilet massif, Variscan Belt, Morocco)

In the Jebilet massif (Variscan belt, Morocco), two peraluminous granodioritic plutons (the Eastern and Central plutons) are spatially associated with a regional shear zone. The pluton includes Tabouchent, Bramram Bamega intrusions, which represent variably eroded portions of an arcuate apical part pluton. intrusions composed biotite ± cordierite-bearing granodiorite that is crosscut by tourmaline-bearing leucogranite, greisenized in cupola. Fluorine, Sn-W (Au) mineralization present while Cu-Au Pb-Zn-Ag-Au mineralizations contact metamorphic aureole around intrusion. Deformation more homogeneous than Tabouchent intrusion where deformation very heterogeneous concentrated within conjugate subvertical meter-scale ductile zones breakdown feldspar resulted transformation to phyllonites quartz + muscovite chlorite. 40Ar/39Ar dating on white mica allowed us date shearing event 305.9 0.9 Ma. Fluid-rock interaction mobilization rare earth elements (REE) other major trace elements. Na Ca typically leached from K volatiles gained. REE mobilisation was decoupled accompanied fractionation between light heavy REE. It mainly controlled alteration magmatic accessory REE-bearing phases, predominantly monazite, followed reprecipitation syntectonic xenotime, Th phosphate, Ce oxide fluorocarbonates. Other typical changes enrichments Sn, W, As Sb. mineralogical chemical recorded similar those greisenization affected leucogranite. They indicate provide pathways for rising acidic fluids exsolved S-type leucogranites.