Figure 41.

Plots of ¹⁸⁷Os/¹⁸⁸Os versus (a, b) Ru/Ir, (c, d) Pd/Ir and (e, f) Pt/Ir for lunar crustal rocks, carbonaceous chondrites (CC), enstatite chondrites (EC), ordinary chondrite (OC) and lunar impact melt breccias (LIMB). Solid lines are mixing models between and average lunar crustal composition and a chondritic composition. The model curves show mixing trajectories of exogenous chondritic impactor material that mixes with endogenous melt generated during impact on the Moon. This form of mixing can potentially explain high Ru/Ir and Pd/Ir seen in some LIMB. Data sources are provided in the text.