Oued Awlitis 001 (OA 001) is a 7.7 x 6.6 x 3.5 cm brownish-grey lunar meteorite with a preserved, translucent fusion crust that was found as two fitting pieces in 2014 in Morocco/Western Sahara. It is a highly feldspathic, moderately equilibrated, clast-rich, poikilitic impact melt rock.
Its poikilitic texture formed due to moderately slow cooling and displays a poikilitic texture of intensely fractured, mm-sized olivine (Fo56-71) and pyroxene (En42.2-59.4 Fs19.6-41.7 Wo6.4-34.0) crystals that enclose euhedral plagioclase phenocrysts. The olivine and pyroxene oikocrysts are compositionally zoned; olivine exhibits Mg-rich cores and Fe-rich rims, whereas pyroxene displays pigeonite rims and augite cores. This crystallized melt groundmass also envelops partly assimilated, <1 mm, angular to subhedral plagioclase clasts.
Between crossed polars, plagioclase clasts and phenocrysts show reduced birefringence, exhibit strongly undulating extinction, and are partly isotropic. Some plagioclase grains exhibit mechanical twinning. The intense shock metamorphic overprint obscures compositional zoning in the plagioclase and some grains are partially transformed to a diaplectic glass.
Plagioclase clasts and the poikilitic groundmass contain euhedral FeNi metal and troilite grains. Ilmenite and Ti-rich spinel are additional accessory phases.
The chemistry of OA 001 suggests it formed from a ferroan anorthositic precursor rock. It was ejected from the Moon during a meteorite impact event about 300 million years ago.
A detailed study of OUED001 is available here:
Credit: Meteoritics and Planetary Sciences
The images here were acquired from thin section NHMV-O105.
Lunar meteorites are meteorites from the Moon. In other words, they are rocks found on Earth that were ejected from the Moon by the impact of an asteroidal meteoroid or possibly a comet. Meteoroids strike the Moon every day. Any rock on the lunar surface that is accelerated by the impact of a meteoroid to lunar escape velocity will leave the Moon’s gravitational influence. Most rocks ejected from the Moon are captured by the gravitational field of either the Earth or the Sun and go into orbit around these bodies. Over a period of a few years to tens of thousands of years, those orbiting the Earth eventually fall to Earth. Those in orbit around the Sun may also eventually strike the Earth up to a few tens of millions of years after they were launched from the Moon.