Anorthite/fluid partitioning of europium at 650°C and 1.3 kbar
D'arco, Philippe; Lagache, Martine
European Journal of Mineralogy Volume 1 Number 6 (1989), p. 783 - 790
published: Dec 21, 1989
manuscript accepted: Aug 22, 1989
manuscript received: Jan 11, 2019
ArtNo. ESP147050106004, Price: 29.00 €
Abstract The partitioning ofEu between synthetic anorthite and Cl-bearing fluids is studied at 650 °C and 1.3 kbar, as a function of the chloride concentration of the fluids. The partition coefficient strongly depends on the composition of the solution. The incorporation of Eu into anorthite is enhanced as the chlorinity decreases. At a given chlorinity, the partition coefficient depends on the Eu concentration in anorthite, for example, it decreases from 9-10 to 4 and from 2-3 to 0.1 as the concentration ofEu in anorthite increases from 0.1 to about 15000 ppm, for 0.5 and 3.0 mole Cl per liter solutions, respectively. It can be shown independently that europium occurs exclusively in the trivalent state in these experiments and that its incorporation into anorthite is not a single cation exchange reaction, but also involves trapping in extended defects. The relative importance of these processes cannot be assessed from the results given here, but the partition coefficients obtained are in agreement with previously published data. They should thus be useful in modelling the hydrothermal geochemistry of REE.