MAJOR ELEMENT COMPOSITION OF GLASSES IN THREE APOLLO 15 SOILS

Abstract

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 compositionsGreen 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