Lunar Meteorite: Northwest Africa 13259

Thin section of Northwest Africa 13259. The grayish clasts are anorthositic lithologies. Photo credit: Addi Bischoff

Meteorite Picture of the Day: NWA 13259

from The Meteoritical Bulletin, No. 109

Northwest Africa 13259 (NWA 13259)

northwestern Africa
Purchase: 2018 Oct 26
Mass: 24.4 g (1 piece)

Classification: Lunar Meteorite (feldspathic breccia)

History: The sample was purchased October 26, 2018 in Munich as a single piece of 24.4 g.

Physical characteristics: The piece has a dark appearance with white clasts and no fusion crust. Saw cuts reveal a breccia with numerous angular shaped, mm-sized, white feldspathic clasts set in a predominantly dark gray to black groundmass. Some brownish clasts are also visible. The clasts are smaller than most other lunar breccias, which typically contain cm-sized fragments.

Petrography: (A. Bischoff and K. Klemm, IfP). SEM images show that it is a breccia of different clasts embedded in a fine-grained matrix. The groundmass is partly a melt matrix with abundant pores (vesicles). The lithic clasts primarily consist of highland clasts dominated by anorthositic lithologies, but also fragments with abundant mafic mineral (olivine, pyroxenes) are frequently observed. Typical melt clasts and melt spherules are also present. The plagioclase has been partially transformed into maskelynite. Mineral fragments of olivine, pyroxene, plagioclase (and maskelynite), ilmenite and an SiO2 phase were found. Ubiquitous melt veins and vesicles are present throughout the groundmass. Locally, the rock can be defined as a melt breccia.

Geochemistry:  (A. Bischoff and K. Klemm, IfP) Mineral compositions: Olivine Fa38.4±6.6, range Fa29-56, Fe/Mn=113, n=15; low-Ca pyroxene Fs40.7±19.6Wo16.9±7.4 Fe/Mn=73, n=11; Ca-pyroxene Fs38.0±15.6Wo38.3±3.0, Fe/Mn=74, n=13; plagioclase: An95.8±0.8, n=4, one grain with An59 was also found.

Classification: Lunar, less feldspathic, regolith to melt breccia

Specimens: Type specimen: 4.9 g IfP.

Randy Says…

I have not studied 13259.

More Information

Meteoritical Bulletin Database

NWA 13259