^1,2Yongli Xue,^2,3,4Jinting Kang,^5,4Shiyong Liao,⁶Runlian Pang,^2,3,4Huimin Yu,^2,3,4Zifu Zhao,⁷Zhaofeng Zhang,⁸Bingkui Miao,^5,3,4 Weibiao Hsu,^2,3,4Fang Huang 
Earth and Planetary Science Letters 613, 118171 Link to Article [https://doi.org/10.1016/j.epsl.2023.118171]
¹Key Laboratory of Gemological Design and Testing, School of Jewelry and Art Design, Wuzhou University, Wuzhou, 543002, China
²CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
³Deep Space Exploration Laboratory, University of Science and Technology of China, Hefei 230026, China
⁴CAS Center for Excellence in Comparative Planetology, USTC, Hefei 230026, Anhui, China
⁵Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023, China
⁶State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
⁷Research Center for Planetary Science, Chengdu University of Technology, Chengdu, 610059, China
⁸Institution of Meteorites and Planetary Materials Research, Key Laboratory of Planetary Geological Evolution, Guilin University of Technology, Guilin 541006, China
Copyright Elsevier

Howardite-Eucrite-Diogenite (HED) meteorites represent a large suit of crustal and sub-crustal rocks from the Vesta. This work presents systematic examination of the Ca isotope data on multiple varieties of HED meteorites for a better understanding of the magmatic evolution of the Vesta. Falls and finds possess similar Ca isotope compositions, and no correlation is observed between �44/40Ca and (Sr/Eu*)_n, indicating that terrestrial weathering effect on Ca isotopes is insubstantial. According to the data in literature, the inner solar system may have a homogeneous �44/40Ca and the average of inner solar system bodies (‰0.97±0.03‰) can approximate the composition of bulk silicate Vesta (BSV). Basaltic eucrites define a cluster in �44/40Ca (‰0.95±0.07‰, 2SD, N=15) that is higher than the terrestrial mid-ocean ridge basalts (‰∼0.85‰). Combined with partial melting and magma ocean differentiation modeling, the Ca isotope signatures suggest that eucrites represent the residual melts evolved from a magma ocean formed by primordial Vesta’s moderate-to-high degree melting (20-100%). Diogenites have distinguishingly higher �44/40Ca (‰1.18±0.15‰, 2SD, N=7) than the basaltic eucrites, which displays a negative correlation with the 1000×Lu/Ti ratio and a positive correlation with 1/Ca. However, magma ocean crystallization can only explain diogenites with �44/40Ca higher than 1.17‰, suggesting that diogenites have complicated petrogenesis and are not necessarily cogenetic with eucrites. Diogenites with ‰�44/40Ca<1.17‰ may result from magma-ocean-cumulate partial melts intruding the eucritic crust. Mixing models suggest that the eucritic component in these diogenites may be less than 10%. Two howardites have lower �44/40Ca of ‰0.80±0.04‰ and ‰0.86±0.05‰ than eucrites and diogenites. This signature may reflect the addition of carbonaceous chondritic materials due to impact brecciation.