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Approximately 180 glasses in each of three Apollo 15 soils have been analyzed for nine elements. Cluster analysis techniques allow the recognition of preferred glass compositions that are equated with parent rock compositions Green glass rich in Fe and Mg, poor in Al and Ti may be derived from deep seated pyroxenitic material now present at the Apennine Front. Fra Mauro basalt (KREEP) is most abundant in the LM soil and is tentatively identified as ray material from the Aristillus‐Autolycus area. Highland basalt (anorthositic gabbro), believed to be derived from the lunar highlands, has the same composition as at other landing sites, but is less abundant. The Apennine Front is probably not true highland material but may contain a substantial amount of material with the composition of Fra Mauro basalt, but lacking the high‐K content. Glasses with mare basalt compositions are present in the soils and four subgroups are recognized, one of which is compositionally equivalent to the large Apollo 15 basalt samples

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Chemical, petrographic, isotopic and field studies of igneous‐textured rocks within the Manicouagan structure indicate that they are the product of impact melting. Features of the melt sheet include a high degree of textural variation combined with chemical homogeneity. The textures record a complex thermal history and are due primarily to the interaction of clasts with melt. An inverse correlation between clast abundance and matrix grain size allows the melt sheet to be divided into three vertically gradational units of variable thickness. Chemical homogeneity indicates that the impact melting process has the first order effect of homogenizing heterogeneous target material. The process, however, is not totally effective, because significant (although small) deviations from a calculated average composition exist, particularly in the basal clast‐laden unit. These differences depend on clast composition and abundance. The results presented here are consistent with proposed models for the generation of terrestrial and lunar impact melts.