Lunar Meteorite: Northwest Africa 13967
|from The Meteoritical Bulletin, No. 110
Northwest Africa 13967 (NWA 13967)
Classification: Lunar meteorite (feldspathic breccia)
History: Acquired by Jay Piatek in May 2015 from a Moroccan meteorite dealer.
Physical characteristics: (L. Garvie, ASU) A single irregular, sandblasted stone weighing 251.8 g. No fusion crust is visible. White clasts to 1.5 cm are visible at the surface. In a polished 7 × 3 cm section, gray, tan, and other lightly colored clasts vary in shape from angular to rounded with a maximum size of 1.5 centimeters. The dark matrix is locally vesicular. In a hand sample, there are visible carbonate veins, possibly as a result of terrestrial alternation.
Petrography: (T. Geraci, C. Kroemer, A. Wittmann, ASU) Polymict, angular to sub-rounded feldspathic clasts set in a glassy, vesicular groundmass. Clasts include medium-grained anorthosite, fine-to-medium grained granulite, one ferroan SiO2– and ilmenite-bearing melt, glassy and crystallized impact melts, including spherule fragments. The most common minerals are anorthite, magnesian olivine, and pyroxene; tissintite and corundum occur as components of the glassy groundmass. Less common minerals include SiO2, chromite, troilite, Fe-Ni metal, ilmenite, ZrO2, and zircon. Fractures are primarily filled by calcium carbonate and sometimes strontium-bearing barite, but mafic minerals and metal clasts are commonly not altered or oxidized.
Geochemistry: (T. Geraci, C. Kroemer, A. Wittmann, ASU) Olivine Fa19.1±6.9, range Fa5.3-27.4 (n=79), Low-Ca Pyroxene Fs28.2±14.2Wo4.3±3.0 (n=57), range Fs10.3-62.5Wo2.3-16.5. High-Ca Pyroxene Fs20.1±11.1Wo40.7±4.5, range Fs2.4-41.2Wo28.3-48.3 (n=31). Plagioclase An95.7±1.3Ab4.1±1.1Or0.2±0.1, range An90.2-97.6Ab2.3-9.5Or0.0-0.4 (n=63). Glass (wt% Mg/Al=0.24-0.53, avg. 0.32±0.05 (n=18). Kamacite 7.1±0.1 wt% Ni (range 7.0-7.2 wt%), 0.36 wt% Co (range 0.330.37 wt%). Martensite 10.9±4.1 wt% Ni, range 8.2-18.9 wt% Ni, 10.87±4.01 wt% Co, range 0.42-1.44 wt% Co.
Classification: Achondrite (lunar feldspathic breccia). Shock-lithified.
Specimens: 34 g at ASU; remainder with Jay Piatek.
I have not studied NWA 13967.
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