High pressure and high temperature metal-silicate partitioning of siderophile elements: The importance of silicate liquid composition

摘要: We have determined liquid metal-liquid silicate partition coefficients for Ni, Co, Mo, W, P, Ga, and Ge at 10 GPa 2000°C in a multi-anvil apparatus. Our sample containers were either MgO or Al2O3. The two different capsule materials imposed redox states on our samples as well producing very compositions. run Al2O3 an fO2 1.1–1.4 log units below the iron-wurstite (IW) buffer, 2.3 IW buffer. Although we determine W agree with previous work, obtained some rather surprising results. In experiments reported here decrease decreasing oxygen fugacity which is opposite to what expected. also find that Mo Ga do not increase much expected fugacity, although Ni Co behave more normal manner, their +2 valence elements would predict. Simple analysis of structures melts shows MgO-rich melt considerably depolymerized than Al2O3-rich melt. partitioning behavior all indicates cations are stabilized This accord work compositional effects forsterite-liquid metal between immiscible liquids. results emphasize need thorough investigation variables could potentially effect including composition addition, they suggest mantle may play important role during core formation.