Fig. 7

The propositional layered structure of winonaite parent asteroid (Benedix et al. 2000; Hunt et al. 2018). The highly diverse textures and mineralogies of winonaites suggest a four-layered structure on the early winonaite parent asteroid (i.e., prior to the catastrophic impact breakup event): (1) surface layer consisting of precursor chondritic materials (e.g., NWA 725 and NWA 1463; Benedix et al. 1998); (2) subsurface layer composed of diverse lithologies that experienced limited metamorphism and FeNi–FeS partial melting (e.g., NWA 6448 and Pontlyfni; Floss et al. 2008); (3) deep residues of silicate partial melting (e.g., SAH 02029 and Tierra Blanca; Hunt et al. 2017); and (iv) the incomplete differentiation metal pools (e.g., the IAB iron meteorites; Hunt et al. 2017)