Northwest Africa 2995

Algeria

Find: 2005

Achondrite (lunar feldspathic breccia)

History: A 538 g fully crusted and minimally weathered stone was purchased in Morocco by A. Aaronson in November 2005.

Petrography and Geochemistry: (T. Bunch and J. Wittke, NAU) The feldspathic fragmental breccia contains many highlands fine-grained lithologies. Norite: Orthopyroxene (Fs_26.4Wo₄; FeO/MnO = 66). Olivine basalt: Olivine (Fa_87.2; FeO/MnO = 95), plagioclase (An_84.7). Subophitic basalt: Ca pyroxene (Fs_25–48Wo_37.1–25.9), pigeonite (Fs_27.8–31.7Wo_15.4–9.3; FeO/MnO = 53), olivine (Fa_36.3; FeO/MnO = 90), plagioclase (An₉₇). Gabbro: Olivine (Fa_34.7; FeO/MnO = 95), pigeonite (Fs_28.2Wo_8.9; FeO/MnO = 67), plagioclase (An₉₄). KREEPy-like basalt: Plagioclase (Ab₅₀Or_17.4), K feldspar (Ab_14.3Or₈₃) in addition to silica, phosphate, and Fe-rich pyroxenes. Troctolite: olivine (Fa_30.8; FeO/MnO = 94), plagioclase (An_94.7). Granulitic impact melts: Olivine (Fa₃₁), orthopyroxene (Fs_25.2Wo_3.4), plagioclase (An₉₅). Anorthosite: (An_92.7–96.8), glassy impact melts, coarse-grained mineral fragments, and a 0.350 mm-size grain of meteoritic Ni, Fe-metal (Ni = 6.3, Co = 1.0 [both wt%]). In addition, the assemblage appears to be characterized by large amounts of breccias within breccias with at least four generations of brecciation observed in one centimeter-size breccia clast. Numerous shock-induced melt veins are present along large breccia clast margins as well as isolated melt pockets within clasts. Interior weathering grade is very low, all glasses are fresh, and no apparent terrestrial alteration veins were noted.

Classification: Achondrite (lunar, feldspathic breccia).

Specimens: A 21.2 g type specimen is on deposit at NAU. Aaronson holds the main mass.