Partitioning of Tungsten and Molybdenum Between Metallic Liquid and Silicate Melt

Abstract

The "excess" of siderophile elements in Earth's mantle is a long-standing problem in understanding the evolution of Earth. Determination of the partitioning behavior of tungsten and molybdenum between liquid metal and silicate melt at high pressure and temperature shows that partition coefficients ( D metal/silicate ) vary by two orders of magnitude depending on whether metal segregated from a basaltic or peridotitic melt. This compositional dependence is likely a response to changes in the degree of polymerization of the silicate melt caused by compositional variations of the network-modifying cations Mg 2+ and Fe 2+ . Silicate melt compositional effects on partition coefficients for siderophile elements are potentially more important than the effects of high pressure and temperature.

The influence of carbon on trace element partitioning behavior

“…The comparisons are limited, but they further support the idea that solid metal/liquid metal partitioning data may be used to understand the effects of metallic composition during planetary core formation. Additionally, some metal/silicate partitioning experiments have been carried out in graphitesaturated conditions, without C-free control runs (e.g., Walter and Thibault, 1995;Li and Agee, 2001). Our results 0.1 1 5 4 3 2 1 0 Fig.…”

Evidence for Mo isotope fractionation in the solar nebula and during planetary differentiation

“…This has been interpreted to reflect removal of volatile Mo oxides formed in oxidizing environments (Fegley and Palme, 1985). During planetary differentiation, Mo preferentially partitions into the core and is strongly depleted in the silicate mantle (e.g., Holzheid and Palme, 2007;Newsom and Palme, 1984;Newsom, 1985Newsom, , 1986Righter et al, 1998;Wade et al, 2012;Walter and Thibault, 1995). The magnitude of Mo depletion in the mantle, therefore, can help to assess the pressure, temperature and oxygen fugacity conditions of metal segregation during planetary differentiation (e.g., Wood et al, 2006;Wade et al, 2012).…”

Carbon solubility in core melts in a shallow magma ocean environment and distribution of carbon between the Earth’s core and the mantle

“…To date many high pressure, high temperature experiments on trace element partitioning between metallic melt and silicate melt have been performed in graphite capsules Walter and Thibault, 1995;Jana and Walker, 1997;Righter et al, 1997;Jana and Walker, 1999;Righter and Drake, 2000;Li and Agee, 2001b;Li and Agee, 2001a;Chabot and Agee, 2003;Righter and Shearer, 2003;Chabot et al, 2005). Thus one may expect that there should not be dearth of experimental data on equilibrium partitioning of carbon between metallic and silicate melts.…”