Lunar Meteorite: Aguelt Mahba 001 & 002
likely paired stones
| from The Meteoritical Bulletin, No. 113 Aguelt Mahba 001Tiris Zemmour, Mauritania Lunar meteorite (troctolitic anorthosite) History: Found approximately 14 km northeast of Tenoumer Crater, Mauritania, in 2023. Physical Characteristics: Eleven stones found together. Fusion crust is absent. Surface and interior coloration consists of a pervasive light gray-green background with tiny dark specks scattered throughout. Petrography: (C. Agee, UNM) This meteorite is a troctolitic anorthosite with plagioclase (~80%), olivine (~15%), and pigeonite (~5%), and minor amounts of titaniferous chromite, Ni-rich Fe-metal, and Fe-sulfide. The olivine and pyroxene grains occur primarily as tiny poikiloblastic inclusions within larger plagioclase grains consistent with an overall granulitic texture. Geochemistry: (M. Spilde, UNM) Plagioclase An97.0±1.2Ab2.7±1.0, n=4; olivine Fa38.8±0.2, Fe/Mn=111±8, n=6; pigeonite Fs30.7±3.1Wo12.6±6.5, Fe/Mn=55±5, n=6. Classification: Lunar (troctolitic anorthosite) based on figure 1 in Stoeffler et al. (1980). Specimens: 32.8 g on deposit at UNM, Bachir Salek holds the main mass. |
from The Meteoritical Bulletin, No. 113 Aguelt Mahba 002Tiris Zemmour, Mauritania Lunar meteorite (troctolite melt breccia) History: Found approximately 22 km east-northeast of Tenoumer Crater, Mauritania, in 2023 Physical Characteristics: Seven stones found together. Fusion crust is absent. Surface is dark colored and irregular with numerous vesicles visible. Petrography: (C. Agee, UNM) This meteorite is an anorthositic troctolite melt breccia consisting primarily of fine-grained olivine and lesser amounts of pyroxene poikilitically enclosed in a dominant plagioclase-rich melt host lithology. Abundant vesicles and shock melt are present throughout. Minor amounts of chromite, augite, and Fe-sulfide were detected. Geochemistry: (M. Spilde, UNM) Plagioclase An97.3±0.6Ab2.4±0.6, n=4; olivine Fa35.4±1.3, Fe/Mn=93±7, n=6; pigeonite Fs31.1±3.1Wo7.5±3.5, Fe/Mn=59±4, n=4. Classification: Lunar (anorthositic troctolite melt breccia) nomenclature based on Stoeffler et al. (1980). Specimens: 30 g on deposit at UNM, Bachir Salek holds the main mass. |
Randy Says… I have not studied Aguelt Mahba 001 or 002. I suspect that they are likely paired because both are troctolitic (rocks consisting mainly of plagioclase and olivine), troctolitic rocks are uncommon among lunar meteorites (other troctolitic anorthosites from northern Africa include NWA 12279, NWA 14088, NWA 16189, NWA 16683, and El Milhas 007), the olivine compositions and Mn/Fe ratios are similar, they were found 9 km apart and at this writing there are no other Aguelt Mahba meteorites, both meteorites are large and consist of several pieces without fusion crusts. There are important differences in the descriptions, however: 002 is described as a breccia with vesicular shock melt and 001 is not, FeNi metal is reported in 001 but not in 002, the olivine compositions are not identical, Fa38.8±0.2, Fe/Mn=111±8, n=6 in 001 and Fa35.4±1.3, Fe/Mn=93±7, n=6, and (perhaps most importantly!), the two meteorites were classified by the same team and the classifiers do not suggest pairing. |