Chemical comparisons of the mare basalt exposed units in the Balmer-Kapteyn region with other rock types: (a) comparison in the FeO-Al₂O₃ content space. (b) Comparison in the Al₂O₃-MgO content space. (c) Comparison in the FeO-MgO content space. (d) Comparison in the FeO-TiO₂ content space. Two sets of lunar rock samples are involved: one is 125 returned lunar rock samples by the Apollo and Luna missions and the other is 30 lunar meteorite samples, including 26 unbrecciated basalts from the meteorites of Yamato 793169, La Paz Icefield (LAP) 02005, 02224, 02226, 02436, 03632, Northwest Africa (NWA) 032/479, NWA 4734, NWA4898, and Northeast Africa (NEA) 003, 3 mare basalt clasts of Northeast Africa (NEA) 001 and one KREEP clast of Sayh al Uhaymir (SaU)169. The chemical components of the Apollo and Luna samples are reported by Wieczorek et al. (2006); Zeigler et al. (2006); Fagan & Neal (2016). The chemical components of the meteorites were reported by Warren & Kallemeyn (1993); Gnos et al. (2004); Zeigler et al. (2005); Day et al. (2006); Greshake et al. (2008); Elardo et al. (2014); Haloda et al. (2006, 2009).