Moon Rocks: Mare Regolith

Lunar thin section 70181

This lunar soil is from the Taurus-Littrow Valley area, in a range of mountains between Mare Serenetatis and Mare Tranquillitatis, by the Apollo 17 mission. The samples are mostly from the Serenitatis ejecta blanket and mare basalt fill.

Most of this soil is derived from high-Ti mare basalts, and include fragments of light purplish-brown pyroxene, colorless plagioclase, basalts, orange glass spheres (fire fountain droplets), and Fe-Ti oxides (black grain just below and to the right of center). Many of the dark fragments are devitrified impact glass and agglutinates. The dark grain in the upper left, with a colorless bubble inside, is an agglutinate. Here, the agglutinates and glass are black. In cross-polarized light the discrete pyroxene and plagioclase grains can easily be distinguished. Field width is 1.6 mm.

Views in plane- and cross-polarized light.

Another view at the same magnification, showing discrete pyroxene grains, one nearly colorless, high birefringence olivine grain (center of the lower right quadrant), basalt rock fragments, Fe-Ti oxides, and agglutinate grains. In the center is a plagioclase grain with most of its birefringence gone due to shock-induced disorder of its crystal lattice. Just above and to the right of center is a fine-grained basalt rock fragment with an embayed plagioclase crystal. In cross-polarized light you can see the low and patchy birefringence of the center plagioclase grain. Field width is 1.6 mm.

Views in plane- and cross-polarized light.