Lunar Meteorite: Northwest Africa 16460
| from The Meteoritical Bulletin, No. 113 Northwest Africa 16460 (NWA 16460)(Algeria) Lunar meteorite (basalt) History: Found in the Algeria desert in 2021, three pieces of stone (with a total weight of 450 g) were purchased by JIANG Wei from Khaled Zed in 2023. Physical Characteristics: The stones have a greenish brown color with no fusion crust. Petrography: Small olivine phenocrysts (up to 150 µm) are sparsely set in an intersertal groundmass composed mainly of elongate, zoned clinopyroxene prisms (up to 2.0 mm) and tabular plagioclase laths (up to 2.0 mm). Olivine phenocrysts contain inclusions of hercynite. Significant fracturing is observed in clinopyroxene and olivine grains, whereas the plagioclase laths show only a limited number of fractures. Augite rims are observed on a few pigeonite grains. Acicular ilmenite grains were ubiquitous in the microprobe mount; Ti-rich chromite, troilite, and silica were also observed. The late-stage mesostasis is composed of silica, K-rich glass, Fe-rich olivine, Fe-rich pyroxene, ilmenite, baddeleyite, apatite, and merrillite. In addition, there are a few patches of shock veins and impact melt pockets. Cracks in the microprobe mount are commonly filled with carbonate/sulphate. Modal mineralogy (vol%): clinopyroxene=59, plagioclase=30, olivine=4, opaques (ilmenite + chromite) = 3, silica=1, other (mesostasis + carbonate/ sulfate)= 3. Geochemistry: Mineralogy by EPMA. Pyroxene [Fs22.2-76.1Wo19.3-38.9En1.5-49.0 (n=25); Fe/Mn = 37.3-89.7, average: 61±12] and olivine [Fo14.1-63.9; Fa36.1-85.6; Fe/Mn = 86-108, average: 93±7; (n=13)] grains are igneously zoned. Pyroxene plots in the low-Ti mare basalt region and follows the same trend of NWA 10597 on the Ti# (molar Ti/(Ti+Cr)) vs. Fe# (molar Fe/(Fe+Mg)) diagram. Plagioclase is highly calcic, An86.7±1.6Ab13.0±1.6Or0.3±0.1 (An84.6-91.6Ab8.2-15.0Or0.2-0.6, n=31); Chemical compositions (wt.%; by EDS) of impact melt vein: MgO=5.8±0.5, FeO=21.6±1.0, Al2O3=10.2±0.7, SiO2=43.4±0.9, CaO=11.2±0.3, TiO2=5.3±0.7. Classification: (Mei A., PMO) Lunar basalt. Specimens: 20 g at PMO. |
| Randy Says… I have not studied Northwest Africa 16460. |
More InformationMeteoritical Bulletin Database NWA 16460 |