Northwest Africa 5207

Morocco

Find: 2007

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, 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 metalsulfide spherules. The interior weathering grade is very low.

Mineral/phase chemistry: Orthocumulate olivine, Fa_26.5 (FeO/MnO = 96) and plagioclase, An_99.3. Coarse-grained basalt olivine is Fa₃₀; Ca-pyroxene core, Fs_45.1Wo_30.4 and rim, Fs_62.7Wo_16.8; plagioclase, An_87.7. Fine-grained basalt olivine is Fa_56.9 (FeO/MnO = 93); Ca-pyroxene, Fs_28.5Wo_34.7; plagioclase, An_91.2. 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.