The Effect of Temperature on the Partitioning of Nickel, Cobalt, Manganese, Chromium, and Vanadium at 9 GPa and Constraints on Formation of the Earth’s Core

Conditions of core formation in the earth: Constraints from Nickel and Cobalt partitioning

“…To achieve good separation of the metal and silicate phases, lower temperature runs #Ni20, #Ni24, and #Ni25 were first raised to 2273 K for 2 min and then lowered to their run temperatures. The choices of run durations were based on previous multi-anvil experimental studies that demonstrated that equilibrium was obtained during such run durations (Thibault and Walter, 1995;Gessmann and Rubie, 1998;Li and Agee, 2001;. The experiments #Ni20 and #Ni24, both conducted at 1973 K, gave consistent partitioning results despite the different run durations of 3 hours and 1 h respectively, suggesting that equilibrium was achieved in both runs.…”

“…The presence of an early hydrous magma ocean has potential implications for the initial volatile budget of the Earth. As another example, experimental studies have shown that the oxygen fugacity at the time when metal segregates from silicate will have an important influence on the non-metal content, such as the S, O, or Si-content, of the metal (Kilburn and Wood, 1997;Gessmann and Rubie, 1998;Hillgren et al, 2000). The specific conditions of core formation thus have implications for the identity of the light element(s) in the Earth's core.…”

“…3; using our experimental pressure of 7 GPa and the weighted averages of C 2 calculated from the pressure studies on Figure 5, the value of C 1 for both D(Ni) and D(Co), and the associated error, were calculated. The last constant, C 3 , was calculated by averaging the values of C 3 determined by each of our experiments as well as from all of the appropriate experiments of previous studies (Hillgren et al, 1994(Hillgren et al, , 1996Thibault and Walter, 1995;Ohtani et al, 1997;Righter et al, 1997;Walker, 1997a, 1997c;Ito et al, 1998;Gessmann and Rubie, 1998;Bouhifd and Jephcoat, 2003). By including all available experimental data, any minor effects from differences in silicate and metallic compositions or any systematic error in a given data set were minimized in the final parameterizations.…”

Vanadium K edge XANES of synthetic and natural basaltic glasses and application to microscale oxygen barometry

“…Vanadium is known to exist as V 3ϩ , V 4ϩ , and V 5ϩ in a wide range of geological environments, may exist as V 2ϩ in highly reduced systems, and previous studies have shown that V partitioning between minerals and melt is redox sensitive (Canil, 1997;Hanson and Jones, 1997;Gessmann and Rubie, 1998;Kilburn and Wood, 1998;Canil, 1999;Connolly and Burnett, 1999;Gessmann et al, 1999;Canil, 2002). In this study, we use V valence determinations in basaltic glasses to estimate f O 2 in spots of a few micrometers diameter using synchrotron X-ray absorption fine structure (XAFS) spectroscopy (e.g., Kutzler et al, 1980;Teo, 1986;Bianconi, 1988;Bianconi et al, 1991;Waychunas et al, 1983).…”

Metal–silicate partitioning of cesium: Implications for core formation

“…Because there are several parameters that may influence the partitioning of a given element, including pressure, temperature, metal and silicate composition, and oxygen fugacity, there is a large body of work in print that studies some combination of these parameters (e.g., Jones and Walker, 1991;Li and Agee, 1996;Gessmann and Rubie, 1998;Jaeger and Drake, 2000;Bouhifd and Jephcoat, 2003). Many use the planetary volatility trend (Fig.…”