Solution properties of rare earth elements in silicate melts: Inferences from immiscible liquids

Effect of melt composition on the partitioning of trace elements between titanite and silicate melt

“…Furthermore, matters turn out to be even more complicated, as we observe also some degree of REE fractionation ( Fig. 4 and 6), which was not observed in liquid-liquid partitioning experiments (Watson, 1976;Ryerson and Hess, 1978;Ellison and Hess, 1989). As van Westrenen et al (2000) point out, changes of coordination of trace elements in melts may be the cause for these phenomena.…”

“…Previous work to investigate the influence of melt composition on partitioning was based on elements partitioning between immiscible silicate liquids (among others: Watson, 1976;Ryerson and Hess, 1978;Ellison and Hess, 1989). Results from these studies suggest that partition coefficients for large cations with low charge (e.g., alkalis) should decrease with increasing degree of polymerization of the melt, whereas partition coefficients for highly charged and small cations (REE and HFSE) should increase with increasing polymerization of the melt.…”

“…A similar conclusion was reached by Klemme et al (1995) and Blundy and Dalton (2000) who compared clinopyroxene-carbonatite melt trace element partitioning with clinopyroxene-silicate melt partitioning. Furthermore, there are many other studies that proposed a significant influence of melt composition on element partitioning either by studying the partitioning between immiscible liquids or the thermodynamic activity coefficients of the trace-element oxide component in various melts (e.g., Watson, 1976;Ryerson and Hess, 1978;Dickinson and Hess, 1985;Ellison and Hess, 1989;Horng and Hess, 2000;Kushiro and Mysen, 2002;Linnen and Keppler, 2002;O'Neill and Eggins, 2002). Important factors in this context are both the major element composition of the melt which influences, by stoichiometry, the composition of the crystal and the activity of the trace element in the melt itself (O'Neill and Eggins, 2002).…”

An overview on geochemistry of Proterozoic massif-type anorthosites and associated rocks

“…In course of the present study, the K-rich felsic suite of rocks plot towards SiO 2 end and Fe-rich dioritic rocks plot towards CaO + TiO 2 + MgO + FeO + P 2 O 5 with lack of compositional gap between the rock suites for all the complexes (figure 10). In addition, the Ba content in ferrodiorites (52-1180 ppm) is lower compared to that of K-rich felsic suite of rocks (123-2920 ppm) unlike the experimental results of Ellison and Hess (1991) on liquid immiscibility. Thus, Fe-rich dioritic rocks and K-rich felsic suite of rocks do not appear to be genetically related via liquid unmixing.…”

Trace element partitioning between apatite and silicate melts

“…5). Ellison and Hess (1989) (8) 1r uncertainty quoted in terms of last significant digits À 1r uncertainty by normal error propagation. but this may be due to different melt compositions.…”