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Lunar Meteorite

Northwest Africa 4898

northern Africa

 


Northwest Africa 4898
(photo credit: Chladni's Heirs)

 

NWA 898 in the lab.  Click on image for enlargement.
(photo credit: Randy Korotev)

 

 

from The Meteoritical Bulletin, No. 93, Meteoritics & Planetary Science 43, 571–632 (2007)

Northwest Africa 4898

Morocco
Find: 2007
Mass: 137 g

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.

 

Randy Says…

NWA 4898 is an unbrecciated basalt and an uncommon type of basalt, a feldspathic ("high-Al," 12.4% Al2O3) basalt, the only one among the lunar meteorites.

 

More Information

Meteoritical Bulletin Database

NWA 4898

References

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., 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., 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.

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.

 

 

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Prepared by: Randy L. Korotev
 

Department of Earth and Planetary Sciences
Washington University in St. Louis

Please don’t contact me about the meteorite you think that
you’ve found until you read this and this.

 

e-mailkorotev@wustl.edu

Last revised: 30 May 2019