Titanium isotopic compositions of ureilites, diogenites, and martian meteorites

We report here the high-precision Ti isotope data from a large set of ureilites, diogenites, and martian meteorites. These results show that titanium isotopes can serve as a tracer for initial oxygen fugacity in planetary mantle reservoirs, and applying this new tool suggests that the martian mantle at approximately 4.5 Ga should have a reducing condition, i.e., 0.8 to 1.6 log unit below the iron-wüstite buffer.