REE geochemistry of fluid-rock interaction processes related to Alpine-type fissure vein mineralisation, Rheinisches Schiefergebirge, Germany

摘要

REE patterns of vein minerals and altered wallrocks from Alpine-type fissure vein mineralisation, Rheinisches Schiefergebirge, Germany, are used to reconstruct the fluid evolution and fluid-rock interaction processes. The REE signature of the hydrothermal fluids, inferred from analysis of quartz samples, was mainly inherited from strongly altered fragments of the wallrock pelites. The redox state of the high-temperature fluids (370-420°C) was relatively reducing, as evidenced by negative Eu anomalies of vein quartz. REE patterns of late-stage vein carbonates (ankerite and calcite) indicate a subsequent increase in the oxidation state of Eu as a consequence of significant fluid cooling.