Fig. 1.

The ε⁵⁴Cr variations in different groups of chondrites (the data and reference sources can be found in Tables 4–6), which occur in the order CI = CH ≥ CB ≥ CR > CM ≈ CV ≈ CO ≥CK > EC ≈ RC > OC. The color shades indicate the 2SD variation of different chondrite groups (the blue and green shades show the 2SD uncertainty of all the ECs and OCs respectively; we use the external reproducibility 0.07 to represent the grouping uncertainties ofCIs and CHs since the 2SD uncertainty are less than 0.07. The middle bold dashed line at ε⁵⁴Cr = +0.3 is the ε⁵⁴Cr boundary for non-carbonaceous chondrite (NC) and carbonaceous chondrite (CC) reservoirs. All CK, RC, OC and EC groups have homogeneous ε⁵⁴Cr within their respective groups. The CV and CK chondrites have distinct ε⁵⁴Cr values from one another, whereas the ε⁵⁴Cr for CV, CM and CO chondrites overlap. EC and RC have similar ε⁵⁴Cr features with the Earth-Moon system.