δ44Ca of Stratabound Fluorite Deposits in Burgundy (France): Tracing Fluid Origin and/or Fractionation Processes
Résumé
Combined Sr and Caisotopic tracers have beenappliedto stratabound fluorite deposits in the central part ofBurgundy (France). These deposits are spatially related to an unconformity between aPalaeozoic granitic and metamorphic basement and Late Triassic sediments. The aim of this work is to trace the origin of fluid(s)fromwhich stratabound fluorite deposits formed. We suggest thatthe variations of the δ44CaSWin fluorite (-0.1 to +0.2‰ relative to seawater sw) could be explained by1)precipitation from a fluid dominated by a Ca isotopic signature similar to that of seawater (calcite or dolomite dissolution from the host-rock) and a Sr isotopic ratio higher than seawater (granitic basement) and involves no fractionation, the preferred scenarioor 2)cristallization from a fluid with a lowδ44CaSW(carbonate and silicate sources) involving fractionationprocesses.