Northwest Africa 4898
Achondrite (Lunar basalt)
History: The meteorite was found by an anonymous finder in Northwest Africa and bought by the main mass holder in Quarzazate, Morocco.
Physical characteristics: One fragment almost completely covered with fusion crust weighing 137 g was found.
Petrography: (A. Greshake, MNB). The meteorite exhibits a spherulitic texture of dominantly lath-shaped plagioclase, pyroxene, and skeletal ilmenite. Olivine occurs as single larger crystals often containing Ti-rich chromite inclusions. Plagioclase is Ca-rich and has been completely transformed into maskelynite during shock metamorphism; pyroxene is compositionally zoned Ti-rich pigeonite and augite. Minor phases include FeNi-metal and troilite.
Geochemistry: Plagioclase (An92.6-96.5), olivine (Fa26.3-27.2; FeO/MnO = 73-92), pyroxene (Fs25.1-58.7Wo13.2-34; FeO/MnO = 42-76).
Classification: Achondrite (Lunar basalt); extensive shock, minimal weathering.
Specimens: A total of 21.1 g plus one polished thin section are on deposit at MNB. Ralew holds the main mass.
NWA 4898 is an uncommon type of unbrecciated basalt, a feldspathic (“high-Al,” 12.4% Al2O3) basalt, the only one among the lunar meteorites.
Meteoritical Bulletin Database
Fernandes V. A., Korotev R. L., and Renne P. R. (2009) 40Ar-39Ar ages and chemical composition for lunar mare basalts: NWA 4734 and NWA 4898. 40th Lunar and Planetary Science Conference, abstract no. 1045.
Gaffney A. and Borg L. (2008) What we are learning about the Moon from lunar meteorites. Geochimica et Cosmochimica Acta 72, 12S, A287.
Gaffney A. M., Borg L. E., DePaolo D. J., and Irving A. J. (2008) Age and isotope systematics of Northwest Africa 4898, a new type of highly depleted mare basalt. Lunar and Planetary Science XXXIX, abstract no. 1877.
Greshake A., Irving A. J., Kuehner S. M., Korotev R. L., Gellissen M., and Palme H. (2008) Northwest Africa 4898: A new high-alumina mare basalt from the Moon. Lunar and Planetary Science XXXIX, abstract no. 1631.
Hsu W., Guan Y., Li S., and Wang Y. (2011) REE microdistributions in NWA 4898: A high-Al mare basalt. 74th Annual Meeting of the Meteoritical Society, abstract no. 5062.
Li S.-L. (2023) Pb-Pb age of high-Al basalt Northwest Africa 4898. 86th Annual Meeting of the Meteoritical Society, abstract no. 6185.
Li S., Hsu W., Guan Y., Wang L., and Wang Y. (2016) Petrogenesis of the Northwest Africa 4898 high-Al mare basalt. 1268-1288. Meteoritics & Planetary Science 51, 1268-1288.
Korotev R. L. and Irving A. J. (2021) Lunar meteorites from northern Africa. Meteoritics & Planetary Science, 206–240.
Korotev R. L., Irving A. J., and Bunch T. E. (2008) Keeping up with the lunar meteorites – 2008. Lunar and Planetary Science XXXIX, abstract no. 1209.
Macke R. J., Kiefer W. S., Britt D. T., Irving A. J., and Consolmagno G. J. (2011) Densities, porosities and magnetic susceptibilities of meteoritic lunar samples: Early results. 42nd Lunar and Planetary Science Conference, abstract no. 1986.
Miyahara M., Kozuma K., Ohtani E., Yamaguchi A., Sakai T., Ohfuji H., Tomioka N., Kodama Y. (2019) Shock-induced melting and high-pressure polymorphs in lunar basaltic meteorites. 82nd Annual Meeting of the Meteoritical Society, abstract no. 6014.
Wang T. and Li S.-L. (2022) Diversity of basalts in lunar feldspathic meteorites. 85th Annual Meeting of The Meteoritical Society, abstract no. 6301.
Webb S., Neal C. R., Gawronska A., and Day J. M. D. (2019) Crystal size distribution patterns for lunar meteorites Northwest Africa 12008, 4898, 8632, 3136 and three LaPaz Icefield lunar meteorites. 50th Lunar and Planetary Science Conference, abstract no. 2686.