It is found that the clast population of metabreccias 14006, 14311, 14320, and 14321 has the grain size properties of an extremely immature lunar impact detritus, probably developed by reworking. The modal composition of the mineral clast population and the An- and Fe-derived content of plagioclase clasts indicate that the clastic material of the breccias is derived from three types of igneous rocks: KREEP and high-alumina basalt, anorthositic-noritic-troctolitic rocks, and possibly mare-type basalt.