Li, Be and B abundances in fines from the Apollo 11, Apollo 12, Apollo 14 and Luna 16 missions

Abstract

The concentrations of Li, Be and B have been determined in the Apollo fine samples 10084, 12070, 14141 and 14259 and in a sample of the core tube returned by the automatic probe Luna 16. The abundance patterns of Li, Be and B in the different soil samples are remarkably similar although the concentrations vary by a factor of four to eight being lowest in the Luna 16 sample and highest in the fines from Apollo 14. A strong correlation of Li, B and K was found for the soil samples collected at the four sites. Within larger experimental errors Be is also correlated with these elements. Lunar abundances of Li, Be and B are in good agreement with those in the terrestrial standard basalt BCR-1. Relative to basaltic achondrites and, in particular, relative to chondrites, lunar Li, Be and B are enriched by a factor of up to 100. The Li, Be and B concentrations in the Apollo 12 fines are enriched by factors of three to five relative to the average concentrations reported for the Apollo 12 basalts. This enrichment most probably is caused by the same additional component in the fines which is responsible for the three to four-fold excess of K, rare earth elements and P (KREEP) relative to the basalts returned from the Ocean of Storms. It is shown that the fines from Apollo 12 and 14 can be related to each other by a two-component mixing model, one end member being the Apollo 12 basalts, the other one the fine sample 14141 whose chemical composition seems to very similar to that of the KREEP component.