Geologic Context for Apollo 17 Pristine Samples from Station 3 as Inferred from Remote Sensing Data: Implications for Sample Origin and Diversity

Abstract:

The opportunity to open unstudied and sealed samples from the Apollo 17 mission through the Apollo Next Generation Sample Analysis Program (ANGSA) enables an unprecedented opportunity to study “pristine” samples with 21^st century analytical techniques. ANGSA allows us to use modern remote sensing datasets to constrain what may be contained within a double core tube prior to its detailed analysis (73001/2). Here we use multiple datasets to provide a remote sensing context for Apollo 17’s Station 3 (S3), with a focus on the regolith components that are expected in the double core tube.

Geologic Context from Recent Remote Observations:

Mini-RF Radar data is valuable for assessing regolith properties up the upper meter of the lunar surface. The m-chi deconvolution enables for an assessment of the scattering properties of the regolith and, given the area sampled during Apollo 17, a comparison of regolith properties across the Taurus–Littrow Valley. The regolith at S3 appears to be due to fragments larger than 12.6 cm (l of Mini-RF S-band data), there is a surface and volume scattering component within the upper 1 m of the regolith. There may be more fragments within the upper meter or the deposit is denser due to the emplacement of the light mantle.

Compositional data from the Moon Mineralogy Mapper informs our understanding of what may have been sampled in the drive tube. Knowing that there is variability in the sample composition collected at S3, the data shows that the light mantle is homogenous and similar to the South Massif.

S3 soils and rock fragments were collected along the rim of Ballet crater within the light-mantle landside from the South Massif. Samples 73001/2 were collected ~15 m from the rim of Ballet crater and samples the light-mantle landslide as well. Nearly all fragments collected from S3 are breccias from the South Massif light mantle. Lithic clasts are composed predominantly of non-mare materials. S3 soils were collected from a trench dug on the rim of Ballet crater. From this trench, 5 soil samples were taken. The trench soils exhibit a distinct marbling of light and darker gray material owing to varying agglutinate content (maturity). The soils are reflective of the light mantle materials as breccia is the most common material in the samples but also contain other fragments of interest including basalt and volcanic glass.