Lunar sample 15299.
This sample of regolith breccia was collected by the Apollo 15 mission, which landed in the Apennine Mountains, part of the ejecta rim of Mare Imbrium. This site was within sight of the Hadley Rille, a sinuous valley that is interpreted to be a collapsed lava tube.
Magnification key 20x = 8 mm image width 40x = 4 mm image width 100x = 1.6 mm image width 200x = 0.8 mm image width 400x = 0.4 mm image width 500x = 0.32 mm image width |
20X, plane polarized light.
This image shows a variety of rocks that include anorthositic and basalt fragments, orange glass spheres and fragments, green glass spheres and fragments (colorless, hard to distinguish), and monominerallic fragments in a dark brown glass matrix. Dark blobs may be relic agglutinates, which distinguish this as a regolith breccia.
20X, cross polarized light.
The larger feldspathic fragments and basalt fragments are visible here. The feldspathic fragment on the far left center is anorthosite breccia. The grain in the center of the lower right quadrant is a basalt fragment.
40X, plane polarized light.
Large grayish grain on the right is a highly reworked anorthositic breccia. The grain on the far left appears to be anorthositic.
also.
40X, cross polarized light.
Here it is clear that the right fragment has a rather small proportion of olivine or pyroxene, probably <10%. The grain on the far left has isotropic regions that are maskelynite.
40X, plane polarized light.
Closer view of the larger basalt fragments in this breccia, near center, and a smaller basalt fragment to the left. Orange glass fragments are visible, as are at least four sizable green glass spheres are visible scattered about (colorless to faint green and round).
40X, cross polarized light.
In cross polarized light the larger feldspathic grain at the top appears to be a partially annealed feldspathic breccia.
100X, plane polarized light.
Closeup view of the larger basalt fragment, that also shows the dark brown glassy matrix.
100X, cross polarized light.
No olivine is present in this grain, only plagioclase, pyroxene, and opaques.