Lunar Meteorite: Northwest Africa 5207
from The Meteoritical Bulletin, No. 94
Northwest Africa 5207 (NWA 5207)
Achondrite (lunar feldspathic breccia)
History and physical characteristics: A 101 g stone was purchased in Rissani, Morocco in 2007 by A. Aaronson. The exterior is dark in color.
Petrography (T. Bunch and J. Wittke, NAU): The fragmental matrix contains a wide variety of lithic, glassy, and shocked components that mainly include plagioclase-olivine orthocumulates, recrystallized noritic and troctolitic anorthosites, anorthosites, gabbros and course to fine-grained basalts, microbreccias, shock-melted lithologies, symplectites (from pyroxferroite decomposition), very sparse Apollo-like “green glasses” (A), and irregular-shaped light to dark green glasses (B), some of which are vesicular and contain tiny metal-sulfide spherules. The interior weathering grade is very low.
Mineral/phase chemistry: Orthocumulate olivine, Fa26.5 (FeO/MnO = 96) and plagioclase, An99.3. Coarse-grained basalt olivine is Fa30; Ca-pyroxene core, Fs45.1Wo30.4 and rim, Fs62.7Wo16.8; plagioclase, An87.7. Fine-grained basalt olivine is Fa56.9 (FeO/MnO = 93); Ca-pyroxene, Fs28.5Wo34.7; plagioclase, An91.2. Green glasses (B) in wt %: SiO2 = 43.8; Al2O3 = 18.7; Cr2O3 = 0.50; TiO2 = 0.78; FeO = 12.5; MgO = 7.0; CaO = 15.2; K2O = 0.33 and Na2O = 0.58 (N = 17).
Bulk chemistry: (R. Korotev, WUSL): Na2O = 0.484 wt %; Sc = 15.52 ppm; Cr = 1065 ppm; FeO = 7.56 wt %; Co = 26.7 ppm; Ni = 233 ppm; Th = 1.26 ppm and Ba = 123 ppm.
Classification: Achondrite (lunar, feldspathic breccia).
Type specimen: A total of 20 g is on deposit at NAU. The main mass holder is anonymous.
Northwest Africa 5207 is a basalt-bearing feldspathic breccia. It may be paired with the NWA 2995 clan as it was found about the same time. There are some subtle compositional differences, however, based on my analysis of the sample in the photo above. Also, none of the NWA 2995 clan are described to contain green glasses.
Meteoritical Bulletin Database
Calzada-Diaz A., Joy K. H., and Crawford I. A. (2016) Investigation of lunar meteorites potentially sourced from cryptomare regions. 47th Lunar and Planetary Science Conference, abstract no. 2075.
Korotev R. L. (2013) Siderophile elements in brecciated lunar meteorites. 44th Lunar and Planetary Science Conference, abstract no. 1028.
Korotev R. L. and Irving A. J. (2021) Lunar meteorites from northern Africa. Meteoritics & Planetary Science, 206–240.
Korotev R. L., Zeigler R. A., Irving A. J., and Bunch T. E. (2009) Keeping up with the Lunar Meteorites – 2009. 40th Lunar and Planetary Science Conference, abstract no. 1137.
Korotev R. L, Zeigler R. A., Jolliff B. L., Irving A. J., and Bunch T. E. (2009) Compositional and lithological diversity among brecciated lunar meteorites of intermediate iron composition. Meteoritics & Planetary Science 44, 1287-1322..