11/29/2022 0 Comments Moon meteorite![]() Siderophile element abundances in lunar highlands meteorites have an important bearing on models for lunar core formation. The bulk Al 2O 3 content of about 26 wt% argues in favor of a magma ocean model for formation of the crust, in which the upper crust became enriched in Al 2O 3 by flotation of plagioclase over a primordial intrusion of global extent. For example, the bulk composition of the lunar crust can be estimated from the compositions of the lunar highlands meteorites and the Apollo samples. Lunar highlands meteorites play an important role in interpreting the geological evolution of the Moon. The exterior of the stone is covered in fusion crust, a thin melted zone that was formed when the meteorite fell through the Earth's atmosphere. Lunar meteorite ALHA81005, a lunar highlands breccia, showing a clastic texture. Their oxygen isotopic ratios match those of the Earth/Moon system, and their Fe/Mn ratios and other trace elements, as well as their mineralogy and textures, are similar to those of comparable Apollo and Luna samples.įIGURE 11. Several lines of evidence show that these meteorites come from the Moon. In comparison, the Apollo and Luna missions sampled only a relatively small equatorial region of the near side. Although the mass is small, the scientific importance of the lunar meteorites is that they sample the lunar surface randomly and represent several different source sites distinct from the Apollo sites, including the possibility that they sample the far side of the Moon. In terms of the lunar sample suite that is available for scientific study, the total mass of lunar meteorites is about 2.6 kg, compared with the total material returned by the Apollo and Luna missions of 382 kg and 300 g, respectively. They include samples of anorthositic breccias from the lunar highlands and basaltic breccias and rocks from the mare regions, i.e., they represent the major rock types of the lunar surface. The lunar meteorites are the only group of meteorites for which the source body has been identified unequivocally. Jones, in Encyclopedia of Physical Science and Technology (Third Edition), 2003 IX.B Lunar Meteorites ![]()
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