PALLASITIC METEORITES - IMPLICATIONS REGARDING DEEP STRUCTURE OF ASTEROIDS

Olivine compositions in pallasites exhibit a bimodal distribution and indicate a high degree of internal equilibrium. Cooling rates measured in the metal phases are uniform and consistently lower than those of most iron meteorites. These factors suggest that the pallasites were derived from few parent bodies, and that they crystallized in a highly insulated site - presumably the core of their parent body. Most iron meteorites were derived either from isolated areas closer to the surface or from other parent bodies.