The polymict eucrites

Previous studies of the newly classified polymict basaltic meteorites, the polymict eucrites (PE), are reviewed to synthesize their significance in extraterrestrial volcanism investigations. The PE breccias contain mafic clasts of euritic or basalt materials in different proportions than found in howardites. Comparisons are made of the eucrite suites in PEs, howardites, eucrites, cumulative eucrites and diogenites. The PEs and the howardites are found to be part of a continuum of basaltic achondrite polymict breccia. The basaltic clasts cooled rapidly at the surface of the PEs and are accompanied by larger-cooling deep crustal materials. Some PEs are regolith breccias that have been exposed to the solar wind, which affected the rare gas contents. It is suggested that the more-than-38 specimens found in Antarctica represent only six or eight different meteorites.