1. Carbon isotopic variation in ureilites: Evidence for an early, volatile-rich Inner Solar System
- Author
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Pierre Sansjofre, Richard C. Greenwood, Akira Yamaguchi, Jean-Alix Barrat, Philippe Gillet, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), National Institute of Polar Research [Tokyo] (NiPR), University of Portsmouth, Laboratoire de Sciences de la Terre (LST), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
- Subjects
planetary differentiation ,010504 meteorology & atmospheric sciences ,Geochemistry ,Ureilite ,engineering.material ,ureilite ,010502 geochemistry & geophysics ,01 natural sciences ,Parent body ,Mantle (geology) ,Geochemistry and Petrology ,Chondrite ,[SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology ,Earth and Planetary Sciences (miscellaneous) ,ComputingMilieux_MISCELLANEOUS ,[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography ,0105 earth and related environmental sciences ,[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics ,Olivine ,volatiles ,Geophysics ,carbon isotopes ,13. Climate action ,Space and Planetary Science ,Isotopes of carbon ,engineering ,Terrestrial planet ,[SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology ,Planetary differentiation ,Geology - Abstract
We analyzed the C isotopic compositions of 32 unbrecciated ureilites, which represent mantle debris from a now disrupted, C-rich, differentiated body. The δ 13 C values of their C fractions range from −8.48 to +0.11‰. The correlations obtained between δ 13 C, δ 18 O and Δ 17 O values and the compositions of the olivine cores, indicate that the ureilite parent body (UPB) accreted from two reservoirs displaying distinct O and C isotopic compositions. The range of Fe/Mg ratios shown by its mantle was not the result of melting processes involving reduction with C (“smelting”), but was chiefly inherited from the mixing of these two components. Because smelting reactions are pressure-dependent, this result has strong implications for the size of the UPB, and points to a large parent body, at least 690 km in diameter. It demonstrates that C-rich primitive matter distinct from that represented by carbonaceous chondrites was present in some areas of the early inner Solar System, and could have contributed to the growth of the terrestrial planets. We speculate that differentiated, C-rich bodies, or debris produced by their disruption, were an additional source of volatiles during the later accretion stages of the rocky planets, including Earth.
- Published
- 2017