Petrology of chromite in ureilites: Deconvolution of primary oxidation states and secondary reduction processes

For 7 of the 8 ureilites we conclude that the relatively oxidizing conditions evidenced by the presence of primary or early chromite pertain to the period of high-T igneous processing. The observation that such conditions are recorded almost exclusively in low-Fo samples supports the interpretation that the ureilite FeO-variation was established during igneous processing on the UPB.