New Model for Agglutinitic Glass Formation from Lscc Data

Introduction: Since the return of the first lunar samples it has been well known that glass-welded aggregates (agglutinates) accumulate in lunar soil as the result of multiple processes, many of which are driven by micrometeorite impacts. The proportion of agglutinates increases with increasing exposure to the space environment, and for an individual soil the proportion of agglutinates also increases with decreasing particle size [e.g., 1, 2]. Detailed chemical and petrographic analyses of a suite of mare soils and their agglutinate constituents prepared by the Lunar Soil Characterization Consortium [1] appeared to confirm the “Fusion of the Finest Fraction” model for agglutinate formation (or F) proposed by Papike et al [3]. However, recent LSCC data for highland soils are not consistent with the F model and alternate models for agglutinate formation must be revisited. Instead, we suggest differential melting of soil species may be more consistent with the full range of soil data to date. Mare soils. LSCC data for mare soils were fully consistent with most paradigms for soil formation. As discussed in [1, 2] and shown in Fig 1, the plagioclase component of soils increases with decreasing particle size and the composition of agglutinitic glass clusters near the smallest size fraction (<10μm). It should be noted that agglutinitic glass is heterogeneous [e.g. 4] and standard deviations about the mean are quite large.