Lunar surface composition and particle size: Implications from laboratory and lunar spectral reflectance data

Abstract

Lunar albedo and color data are compatible with participate rock of basic composition such as basalt, but not with crystalline acidic rock such as rhyolite, or with rock glass such as obsidian, or pumice. Laboratory experiments suggest that albedo differences on the moon could be accounted for by variations in mean particle size. According to this model there need not be major compositional differences between highland and maria regions; however, compositional inhomogeneities within the basic-rock family are implied by areal color differences within the dark maria. The reddening of lunar features with increasing phase angle and a broad minimum in the lunar reflectance spectrum at 1.0 μ are duplicated in the laboratory with basalt powders.