Nominally anhydrous minerals (NAMS), such as plagioclase, may represent a significant volatile reservoir as their low intrinsic volatile content is multiplied many times by their large volumetric abundance. This study reports the volatile concentration of CO 2 , H 2 O, F, P 2 O 5 , S, and Cl in shocked plagioclase from three paired lunar troctolites, Northwest Africa (NWA) 5744, NWA 8676, and NWA 10140, to assess the volatile inventory of the early lunar crust. Measured volatile abundances are typically < 5 ppm, except for P 2 O 5 , which is as high as ∼ 300 ppm. Calculated parental melt estimates range from ∼ 3.2 to 238 ppm H 2 O, 2.3 to 213 ppm F, and 0.13 to 1971 ppm Cl. Whilst the lower ends of these ranges are in keeping with literature values, the higher ends of these ranges may indicate heterogeneity in the early Moon's volatile distribution. The cause or causes of any heterogeneity will remain poorly defined until complementary isotopic data (e.g., H, Cl) and distribution coefficients are known for lunar conditions.
Barrett et al. (Wed,) studied this question.