Accretion of primitive planetesimals: Hf-W isotopic evidence from enstatite chondrites

Enstatite chondrites have often been considered to be closely related to th e material from which Earth accreted. However, tungsten isotopic data revea l clear differences. Moreover, the silicate and metal fractions define dist inct initial H-182/Hf-180 corresponding to a 13.8 +/- 5.3 million year appa rent age difference. Internal reequilibration does not provide a ready expl anation for this result. Larger scale redistribution of tungsten is more li kely, such as may have occurred during collisions between planetesimals.