Fractionation of Trace Elements in Carbonates and Sulfides

The fractionation of trace elements between aqueous solutions and minerals is a powerful tool to obtain information about specific geochemical environments at low temperatures near the earth surface. A special designed crystallisation method is applied for the incorporation of Ni2+, Co2+, and Mn2+ into galena (PbS) und covellite (CuS) as well as Sr2+ into calcite by the diffusion of H2S and CO2 through a polyethylene membrane. The fractionation of Sr2+, Ba2+, Cd2+, and Ca2+-isotopes between aqueous solutions and aragonite is studied from 10 to 50°C. The value of the distribution coefficient depends on the temperature which may be applied to the precipitation of aragonite in sea water.