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)
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].
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].
