Chromium Isotopic Constraints on the Origin of the Ureilite Parent Body
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
Chromium Isotopic Constraints on the Origin of the Ureilite Parent Body. / Zhu, Ke; Moynier, Frédéric; Schiller, Martin; Wielandt, Daniel; Larsen, Kirsten K.; van Kooten, Elishevah M. M. E.; Barrat, Jean-Alix; Bizzarro, Martin.
In: Astrophysical Journal, Vol. 888, No. 2, 126, 2020.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - Chromium Isotopic Constraints on the Origin of the Ureilite Parent Body
AU - Zhu, Ke
AU - Moynier, Frédéric
AU - Schiller, Martin
AU - Wielandt, Daniel
AU - Larsen, Kirsten K.
AU - van Kooten, Elishevah M. M. E.
AU - Barrat, Jean-Alix
AU - Bizzarro, Martin
PY - 2020
Y1 - 2020
N2 - We report on the mass-independent Cr isotope compositions of 11 main group ureilites and an ureilitic trachyandesite (ALM-A). The 54Cr/52Cr ratios for main group ureilites vary from −1.06 ± 0.04 to −0.78 ± 0.05 and averaged at −0.91 ± 0.15 (2SD, N = 18) including the data from literature. We argue that this variation reflects primitive mantle heterogeneities within the ureilite parent body (UPB). As such, this body did not experience a global-scale magma ocean, which is consistent with heterogeneous O isotope in ureilites. Furthermore, the ε54Cr values, Mn/Cr ratios, C isotope ratios, Mg# values, and Fe/Mn ratios in the olivine cores of ureilites are correlated with each other, which suggests the mixing of ureilite precursors from at least two reservoirs, rather than a smelting process or the oxidation from ice melting. All the ureilite samples (including the ALM-A) fall on a well-defined 53Mn–53Cr isochron corresponding to a 53Mn/55Mn ratio of (6.02 ± 1.59) × 10−6, which translates to an age of 4566.7 ± 1.5 Ma (within 2 Ma after calcium-aluminum-rich inclusions; CAIs) when anchored to the U-corrected Pb–Pb age for the D'Orbigny angrite. This old age indicates early partial melting on the UPB, consistent with the early accretion of the UPB (within 1 Ma after CAIs) predicted by thermal modeling. Furthermore, there is a 4∼5 Ma age difference between the external isochron in this study and internal isochron ages for the feldspathic clasts in polymict ureilites, which likely reflects an impact history during the early evolution of the UPB.
AB - We report on the mass-independent Cr isotope compositions of 11 main group ureilites and an ureilitic trachyandesite (ALM-A). The 54Cr/52Cr ratios for main group ureilites vary from −1.06 ± 0.04 to −0.78 ± 0.05 and averaged at −0.91 ± 0.15 (2SD, N = 18) including the data from literature. We argue that this variation reflects primitive mantle heterogeneities within the ureilite parent body (UPB). As such, this body did not experience a global-scale magma ocean, which is consistent with heterogeneous O isotope in ureilites. Furthermore, the ε54Cr values, Mn/Cr ratios, C isotope ratios, Mg# values, and Fe/Mn ratios in the olivine cores of ureilites are correlated with each other, which suggests the mixing of ureilite precursors from at least two reservoirs, rather than a smelting process or the oxidation from ice melting. All the ureilite samples (including the ALM-A) fall on a well-defined 53Mn–53Cr isochron corresponding to a 53Mn/55Mn ratio of (6.02 ± 1.59) × 10−6, which translates to an age of 4566.7 ± 1.5 Ma (within 2 Ma after calcium-aluminum-rich inclusions; CAIs) when anchored to the U-corrected Pb–Pb age for the D'Orbigny angrite. This old age indicates early partial melting on the UPB, consistent with the early accretion of the UPB (within 1 Ma after CAIs) predicted by thermal modeling. Furthermore, there is a 4∼5 Ma age difference between the external isochron in this study and internal isochron ages for the feldspathic clasts in polymict ureilites, which likely reflects an impact history during the early evolution of the UPB.
KW - Astrochemistry
KW - Cosmochemistry
KW - Cosmochronology
KW - Asteroids
KW - Small solar system bodies
KW - Solar system planets
KW - Isotopic abundances
KW - Nucleosynthesis
U2 - 10.3847/1538-4357/ab5af7
DO - 10.3847/1538-4357/ab5af7
M3 - Journal article
VL - 888
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 126
ER -
ID: 240693958