Lunar crystalline rock

Yttrium has been found in samples of lunar crystalline rocks (namely in relatively yttrium-rich mineral and grain-si/e fractions, light and dark clasts) collected during the Apollo 11-15 and Luna 16 missions. A relatively high amount of yttrium was found in these samples (Gmelin et al. 1980). Indeed, the proportion of yttrium to rare earth elements (REE including ratios and correlations of Y and REE to other elements) was used as a criterion for the classification of lunar rocks. Yttrium and Rare Earths were also a subject of study in the space, for example, in stellar spectra in the solar atmosphere, and in different types of meteorites and mesosiderites. 

The TL curves of samples of lunar material appear at 350 C for lunar fines and 400°C for crystalline rocks (134). The TL is probably the result of an equilibrium between gains from radiation by cosmic rays bombarding the moon s surface combined with the possible presence of radioactivity in the... 

Figure 5 Mare pyroclastic glasses tend to have far higher MgO, yet a similar range in Ti02, compared to crystalline mare basalts. For basalts, plotted data are averages of many literature analyses for basalt types (Table 2), except for lunar meteorites, which are individual rocks (shown with smaller filled squares). Other data sources are as cited by Arai and Warren (1999), i.e., primarily the compilation of Taylor et al. (1991) updated from Arai and Warren (1999) by adding lunar meteorites Dhofar 287 and NWA032 (but not the cumulate NWA773, 26 wt.% MgO, excluded because its composition is presumably unrepresentative of its magma type).

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