ALHA 81005 Meteorite: Chemical evidence for Lunar Highland Origin


  • J. C. Laul,

  • M. R. Smith,

  • R. A. Schmitt


Based on the well-established characteristic lunar and meteoritic ratios of FeO/MnO, Cr2O3/V and K/La, and REE patterns, ALHA 81005 meteorite is undoubtedly of lunar highland origin. The ALHA 81005 meteorite is an anorthositic gabbro (72% Pl) and matches closely in chemical composition to Apollo 15 15418 and Luna 16 21013 highland rocks. The rock is a non-KREEPY and VLT type. The siderophiles Au, Ni and Ir content is high (1.5% Cl equivalent) and similar to other lunar highland breccias. The clast has a different ancient meteorite component than the bulk and matrix. The meteorite has a young terrestrial age implying a recent lunar cratering event. Therefore, during major lunar basins formation in early eons, the earth must have received a significant amount of lunar material which is now mixed in the crust. The finding of a lunar meteorite lends credibility to the suggestion that SNC achondrites may come from Mars.