Partition of Ni between olivine and sulfide: the effect of temperature,f_{{text{O}}_{text{2}} } and f_{{text{S}}_{text{2}} }

The experimental distribution coefficient for Ni/ Fe exchange between olivine and monosulfide (K_D3) is 35.6±1.1 at 1385° C, (f_{{text{O}}_{text{2}} } = 10^{ - 8.87} ,f_{{text{S}}_{text{2}} } = 10^{ - 1.02} ) , and olivine of composition Fo96 to Fo92. These are the physicochemical conditions appropriate to hypothesized sulfur-saturated komatiite magma. The present experiments equilibrated natural olivine grains with sulfide-oxide liquid in the presence of a (Mg, Fe)-alumino-silicate melt. By a variety of different experimental procedures, K _D3 is shown to be essentially constant at about 30 to 35 in the temperature range 900 to 1400° C, for olivine of composition Fo97 to FoO, monosulfide composition with up to 70 mol. % NiS, and a wide range of (f_{{text{O}}_{text{2}} } ) and (f_{{text{S}}_{text{2}} } ) .