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Northwest Africa 2402
Basic information Name: Northwest Africa 2402
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 2402
Observed fall: No
Year found: 2017
Country: (Northwest Africa)
Mass:help 500 g
Meteoritical Bulletin:  MB 108  (2020)  Lunar
Recommended:  Lunar    [explanation]

This is 1 of 107 approved meteorites classified as Lunar.   [show all]
Search for other: Lunar meteorites
Comments: Approved 7 Nov 2019
Writeup from MB 108:

Northwest Africa 2402 (NWA 2402)

(Northwest Africa)

Purchased: May 2017

Classification: Lunar meteorite

History: The meteorite was exported from Morocco to Tucson where it was purchased by N. Gessler.

Physical characteristics: Weathered reddish-black fusion crust on one side. Dark-gray matrix with abundant clasts, frequently angular in outline, up to 8 mm, varying from white to near-black.

Petrography: The texture is an immature regolith breccia, gradational with polymict nonregolithic (fragmental) breccia. A finite but very sparse abundance of regolithic spheroids (two identified in a large thin section) is the main indication for an immature regolith breccia. The groundmass is mafic-rich. Clasts vary in mode from Ti-poor basaltic to anorthositic (9/10 plagioclase, granulitic). Pyroxene is the dominant mafic silicate; and in the groundmass, in the basaltic clasts, and in relatively coarse mineral clasts, mostly shows a similar fine, roughly µm-scale, exsolution. Lithic clast textures include vitrophyric, fine-scale poikilitic (impact melt?), granulitic, and medium-grained basaltic. One unusual clast, 0.4 × 0.2 mm, consists of a symplectitic intergrowth of roughly 50% ferroan olivine, 35% silica and 15% augite (with very fine-scale exsolution lamellae of low-Ca pyroxene) and 0.5% ilmenite.

Geochemistry: On the pyroxene quadrilateral, compositions (28 analyses) scatter evenly across the space bounded by Fs22Wo9, Fs54Wo6, Fs52Wo21 and Fs38Wo39; the last being the pyroxene of the olivine-silica-pyroxene simplectitic clast. Pyroxene FeO/MnO averages 65.5. The olivine of the sympectitic clast is uniformly Fa83. Olivine elsewhere is as magnesian as Fa28. Plagioclase (8 analyses) ranges from An88 to An97, the latter extreme coming from the same poikilitic highland clast that yielded the Fa28 olivine. Two glassy spheroids have VLT-mare compositions similar to glasses in Yamato 793274. The bulk composition, determined by INAA and fused-bead EPMA applied to 2 chips totaling 760 mg, has 18 wt% Al2O3, 12.2 wt% FeO and Mg/(Mg+Fe) = 57 mol%, a combination that (along with the spheroids, and the compositional spread and slight exsolution in much of the pyroxene) suggests a significant VLT-mare component. The bulk TiO2 is only 0.58 wt%. The bulk-rock concentration of the arch incompatible element Th is 1.0 µg/g. Geochemically as well as petrographically, this sample strongly resembles the first highland-mare mixed breccia, Yamato 793274.

Classification: Lunar mixed highland-mare breccia

Specimens: Main mass with Gessler, type specimen at UCLA.

Data from:
  Table 0
  Line 0:
Place of purchase:Tucson
Date:P May 2017
Mass (g):500
Shock stage:S4
Weathering grade:moderate
Fayalite (mol%):28-83 (varies by clast)
Ferrosilite (mol%):highly diverse
Wollastonite (mol%):highly diverse
Classifier:P. Warren, UCLA
Type spec mass (g):24
Type spec location:UCLA
Main mass:Nick Gessler
Comments:Gessler's address: 2010 Calgary Lane, Los Angeles, CA 90077; submitted by Paul Warren
   and collections
UCLA: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, United States (institutional address; updated 17 Oct 2011)
Gessler: Nicholas Gessler, 2010 Calgary Lane, Los Angeles, CA 90077, United States (private address; updated 7 Jul 2016)
References: Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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     This is 1 of 9772 approved meteorites from (Northwest Africa) (plus 1862 unapproved names)

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