The REE content of some hydrothermal fluids

Abstract

REE concentrations were determined in solutions from submarine hydrothermal vents on the East Pacific Rise and, for the first time, from continental geothermal fields in Tibet and Bulgaria. They indicate that, in hydrothermal systems, REE are immobile at temperatures below 350°C and for water/rock ratios of <105. ε{lunate}Nd-values of submarine solutions and anhydrites (+4.7 to +6.2) suggests recharge on the sedimentcovered flanks of the ridge. Carbonate anions, as measured by alkalinity, appear to increase the solubility of heavy REE somewhat, but not to the extent that substantial amounts of REE could be driven out from rocks by hydrothermal activity. © 1986.