Mineralogical and chemical study of Divnoe ungrouped primitive achondrite

Hikari Hasegawa (Univ. Tokyo), Takashi Mikouchi (Univ. Tokyo), Akira Yamaguchi (NIPR), Naoki Shirai (Tokyo Metropolitan University), Mitsuru Ebihara (Tokyo Metropolitan University)

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Accretion of Earth’s volatiles:
In terms of their H and N isotopes, as well as
volatile element abundances, the CI and CM like
bodies are the most likely the sources of Earth’s
volatiles [5, 15]. Since the bulk H and N isotopic
compositions of CI and CM chondrites probably
evolved during their aqueous alteration, the Earth’s
building blocks cannot have accreted them until after
alteration was complete, which was ≥4-5 Myr after
CAIs [13] and after Mars-sized embryos had begun
to form [28].