Figure 4.

Plots of Pd/Os versus (a) Pt/Os and (b) Ir/Os for primitive achondrites and chondrites, with calculated compositions of metal residues. Shown are chondrite (Horan et al. 2003; Fischer-Gödde et al. 2010) ureilite (Rankenburg et al. 2008) and brachinite-like achondrite compositions (Day et al. 2012b). The melt calculations model the composition of residues that result from single episodes of batch melting. The starting HSE composition is the bulk composition of Orgueil with concentrations adjusted assuming that all of the HSE were originally in metal and that metal comprises 5% of the bulk. Curves show compositions of residues resulting from no sulfur, and 25% sulfur. Fractions of residue are labelled and are in increments of 5%. Solid-metal–liquid-metal D values were calculated using the parameterization of Chabot and Jones (2003). Carbonaceous chondrite [CC]; enstatite chondrite [EC]; ordinary chondrite [OC].