We study samples from the Apollo missions in my laboratory. Here I present a few photographs of the samples. The rocks in the photographs are not a representative suite of lunar rocks because our studies focus on breccias from the highlands, not so much mare basalts.
Lithic Fragments from the Regolith
Lithic (rock) fragments from the 2-4-mm grain-size fraction of the Apollo 11 regolith (sample 10085). Apollo 11 landed in Mare Tranquillitatis, so many of the fragments are basalts. Also visible here are impact glass spherules, agglutinates and regolith breccias formed from the local soil, and breccias from the feldspathic highlands (the lightest colored fragments). We prefer the term lithic fragment to rock fragment because the glass spherules are not really rocks. Photo credits: Randy KorotevLithic fragments from another Apollo 11 sample, 10002. Photo credit: Randy KorotevLithic fragments from the 1-2-mm grain-size fraction of the Apollo 16 regolith (sample 65902). The Apollo 16 mission landed in the feldspathic highlands, so there are few, if any, mare basalts here. The rocks are mainly crystalline impact-melt breccias, regolith breccias, fragmental breccias, and a few pieces of largely unbrecciated anorthosite (the white fragments). Photo credit: Randy Korotev
Pristine Cataclastic Anorthosite
Two fragments of Apollo 16 sample 60025, a pristine cataclastic anorthosite. This samples consists almost entirely of plagioclase feldspar. The term cataclastic implies that it is shocked and fractured by meteorite impacts, which causes the opaque white color as opposed to the translucence one sees in terrestrial plagioclase-rich rocks of this size. A millimeter scale is just visible in the lower left corner. Photo credit: Randy KorotevA petrographic thin section of anorthosite sample 60025 (crossed polarizers). Nearly all the minerals are plagioclase. The fractures reflect the “cataclastic” nature of the anorthosite. fov = 2.3 cm. Photo credit: Randy Korotev
Pristine Magnesian-Suite Norites
Three fragments of Apollo 17 sample 77215, a pristine, cataclastic, magnesian-suite norite. The term cataclastic implies that it is shocked and fractured by meteorite impacts, which causes the opaque white color. Millimeter scale above. Photo credit: Randy KorotevThin section (partially crossed polarizers) of Apollo 17 magnesian-suite norite 78235. The dark material with vesicles is glass. The crystalline material (plagioclase and orthopyroxene) has been heavily shocked. fov = 2.5 cm. Photo credit: Randy Korotev
Impact-Melt Breccias
Two fragments of Apollo 16 sample 60035, a feldspathic impact-melt breccia. Compositionally, it is quite similar to several feldspathic lunar meteorites. Millimeter scale. Photo credit: Randy KorotevFragments of Apollo 16 sample 65015, a poikilitic impact-melt breccia of KREEPy noritic composition. The greenish color is characteristic of these rocks. Millimeter scale. Photo credit: Randy KorotevFragments of the poikilitic impact-melt-breccia lithology in Apollo 17 sample 77075. Like 65015, the composition is noritic and KREEPy. Millimeter scale. Photo credit: Randy KorotevFragments of Apollo 17 sample 77115, a vesicular, poikilitic impact-melt breccia. The vesicles indicate that there were gas bubbles in the melt when it solidified. It is not known what the identity of the gas was. Millimeter scale. Photo credit: Randy Korotev
Granulitic Breccias
Granulitic breccias are metamorphic rocks. They are breccias that have been “cooked,” usually at depth, by the heat of an impact. Other words used to describe these rocks are granoblastic breccia, poikiloblastic breccia, granulitic impactite, and metabreccia (to imply that the rock has been metamorphosed). All these rocks are feldspathic (>60% plagioclase). A characteristic of granulitic breccias is that the clasts are not as obvious as in other kinds of breccias.
Slice of Apollo 15 sample 15418. Portions, at least, have the texture of a granulitic breccia. Millimeter scale. Photo credit: Randy KorotevFragments of Apollo 16 sample 67215, now generally regarded as a granulitic breccia. Millimeter scale. Photo credit: Randy KorotevFragments of Apollo 17 granulitic breccia 77017. Photo credit: Randy KorotevFragments of Apollo 17 granulitic breccia 78155. Photo credit: Randy KorotevFragments of Apollo 17 granulitic breccia 79215. This one looks most like the NWA 3163 clan of lunar meteorites Photo credit: Randy Korotev
