Opaque Minerals of the Lunar Rocks and Dust from Mare Tranquillitatis

Abstract

The opaque minerals in the lunar rocks 10047, 10050, 10057, 10059, 10068 and in the dust were studied. Rock 10047 contains ilmenite as a main component besides Al-bearing chromian ulvöspinel, a new Ti, Fe, Zr, Y, Ca silicate, troilite, cobaltian α Fe, minor hafnian baddeleyite and dysanalyte. Dysanalyte contains Ca, Ti, and Fe as major elements and shows concentrations (rare earth elements together ≈ 10 percent) of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Hf, Y, and Zr plus traces of Nb, Ba, and Na. The chemistry of ilmenite in the igneous rocks shows no appreciable variations. A new mineral of the solid solution series MgTi₂O₅-FeTi₂O₅ has also been encountered in the polymict breccias. The microbreccias and the fines contain meteorite debris indicating an impact origin.