The complete (or near complete) differentiation of a chondritic parent body is believed to result in an object with an Fe-Ni core, a thick olivine-dominated mantle and a thin plagioclase/pyroxene crust. Compositional groupings of iron meteorites give direct evidence that at least 60 chondritic parent bodies have been differentiated and subsequently destroyed. A long standing problem has been that our meteorite collections, and apparently our asteroid observations as well, show a great absence of olivine-dominated metal-free mantle material. While the basaltic achondrites (HED meteorites) represent metal-free pyroxene-dominated crustal samples, the isotopic and geochemical evidence implies that this class is derived from only one parent body (perhaps Vesta). Thus the meteoritic (and perhaps astronomical) evidence also suggests a great absence of crustal material resulting from the collisional disruption of numerous parent bodies.
Anders Meibom, Stéphane Laurent Escrig, Anders McCarthy, Pierre Vonlanthen
Philippe Gillet, Cécile Hébert, Marco Cantoni, James Badro, Farhang Nabiei, Charles-Edouard Boukaré
Philippe Gillet, Marco Cantoni, James Badro, Susannah McGregor Dorfman, Farhang Nabiei, Charles-Edouard Boukaré