  We determined the mineral-melt partition coefficients (Di's) and the
compositional and/or temperature dependency between grossite, melilite,
hibonite, olivine and Ca-, Al-inclusion (CAI)-type liquids for a number of
light (LE), high field strength (HFSE), large ion lithophile (LILE), and rare
earth (REE) elements including Li, Be, B, Sr, Zr, Nb, Ba, La, Ce, Eu, Dy, Ho,
Yb, Hf, Ta, Th. A series of isothermal crystallization experiments was
conducted at 5 kbar pressure and IW+1 in graphite capsules. The starting
compositions were selected based on the calculated and experimentally confirmed
phase relations during condensation in CI dust-enriched systems (Ebel and
Grossman, 2000; Ebel, 2006; Ustunisik et al., 2014). Partition coefficients
between melt and gehlenite, hibonite, and grossite show that the trace element
budget of igneous CAIs is controlled by these three major Al-bearing phases in
addition to pyroxene. In general, LE, LILE, REE, and HFSE partition
coefficients (by mass) decrease in the order of Di(Gehlenite-Melt) >
Di(Hibonite-Melt) > Di(Grossite-Melt). Results suggest that Di(Gehlenite-Melt)
vary by a factor of 2-3 in different melt compositions at the same T (~1500 C).
Increased melt Al and Ca, relative to earlier work, increases the compatibility
of Di(Gehlenite-Melt), and also the compatibility of Di(Hibonite-Melt),
especially for La and Ce. Olivine partitioning experiments confirm that olivine
contribution to the trace element budget of CAIs is small due to the low
Di(Olivine-Melt) at a range of temperatures while D-Eu, Yb(Olivine-Melt) are
sensitive to changes in T and oxygen fugacity. The development of a predictive
model for partitioning in CAI-type systems would require more experimental data
and the use of analytical instruments capable of obtaining single phase
analyses for crystals < 5 micron.
