Lunar Meteorite: Northwest 14137 & 14526

possible pairs or launch pairs?

Northwest Africa 14137. Photo credit: Doug Chenin
Two endcuts of NWA 14137. Photo credits: Doug Chenin

from The Meteoritical Bulletin, No. 110

Northwest Africa 14137 (NWA 14137)

(Northwestern Africa)
Find: 2021
Mass: 77 g (1 piece)

Lunar meteorite (basalt)

History: Reportedly found in 2021 and purchased by Doug Chenin in 2021 from a meteorite dealer in Mauritania.

Physical characteristics: Single stone, with smooth to irregular exterior surface, no fusion crust present, and numerous vesicles pits visible in hand sample. Polished saw cuts reveal a fine-grained mix of dark-gray and light-brown grains, many dark shock melt pockets present. Unbrecciated.

Petrography: (C. Agee, UNM) Backscattered electron images shown igneous-zoned olivines and pyroxenes. Maskelynite makes up approximately 25% of the modal mineralogy, ubiquitous acicular ilmenite ~5%, minor ulvospinel, troilite, chromite and silica observed. Quench melt pockets are present throughout.

Geochemistry: (A. Ross and C. Agee, UNM) Olivine Fa57.7±21.1, Fe/Mn=99±4, n=9; clinopyroxene Fs46.1±19.2Wo25.1±5.6, Fe/Mn=64±12, n=12;, maskelynite An88.5±0.8Ab11.0±0.8, n=6. Quench melt SiO2=43.7±0.7, TiO2=4.1±0.3, Cr2O3=0.24±0.08, Al2O3=10.1±1.2, MgO=5.9±1.6, FeO=22.2±1.0, MnO=0.28±0.02, CaO=10.7±0.5, Na2O=0.42±0.16, K2O=0.12±0.05 (all wt%, 30 μm defocused beam), n=8. Clinopyroxene shows Fe-enrichment trends that are continuous from Mg-augite and Mg-pigeonite to subcalcic-ferroaugite/ferropigeonite.

Classification: Lunar (mare basalt). Based on the TiO2 content of quench melt this is meteorite transitional between low-Ti and intermediate-Ti mare basalt (Giguere et al. 2000).

Specimens: 15.9 g including a probe mount on deposit at UNM, DChenin holds the main mass.

from The Meteoritical Bulletin, No. 110

Northwest Africa 14526 (NWA 14526)

(Northwestern Africa)
Purchased: 2021
Mass: 505 g (1 piece)

Lunar meteorite (basalt)

History: Found in northwest Africa, purchased by Luc Labenne from meteorite dealer in 2021.

Physical characteristics: Single stone, with smooth to irregular exterior surface, no fusion crust present, and numerous vesicles pits visible in hand sample. Polished saw cuts reveal a fine-grained mix of dark-gray and light-brown grains, many dark shock melt pockets present. Unbrecciated.

Petrography: Single stone with a smooth to irregular exterior surface with indentations resembling large vesicles; patches of sandblasted fusion crust were also observed. Freshly broken surface reveals a fine-grained mix of dark gray and light brown grains, shiny maskelynite patches are present. Unbrecciated.

Geochemistry:(A. Ross and C. Agee, UNM) Olivine Fa60.6±15.3, Fe/Mn=104±5, n=10; clinopyroxene Fs36.3±9.3Wo16.8±7.9, Fe/Mn=60±7, n=19; maskelynite An85.8±5.6Ab13.6±5.6, n=6. Quench melt SiO2=44.4±0.4, TiO2=2.7±0.2, Cr2O3=0.46±0.01, Al2O3=8.3±0.7, MgO=10.7±0.6, FeO=24.5±0.8, MnO=0.30±0.02, CaO=8.8±0.3, Na2O=0.30±0.04, K2O=0.13±0.04 (all wt%, 30 micron defocused beam), n=4. Clinopyroxene shows Fe-enrichment trends that are continuous from Mg-augite and Mg-pigeonite to subcalcic-ferroaugite.

Classification: Lunar (mare basalt). Based on the TiO2 content of quench melt this is meteorite is a low-Ti mare basalt (Giguere et al., 2000).

Specimens: 20 g including a probe mount on deposit at UNM, Labenne holds the main mass.

Randy Says…

I have not studied Northwest Africa 14137. If the basalt has 4% TiO2, then it is likely a new meteorite.

I am putting these two meteorites on the same page so that others can compare the descriptions, which I find to be similar. It is significant, however, that the classifiers do not make this suggestion as they’ve seen both rocks, so maybe I’m overlooking something important. I am not too concerned about the difference in TiO2 in the quench melt, 4.1±0.3% vs. 2.7±0.2%. These two rock need further study.

More Information

Meteoritical Bulletin Database

NWA 14137 | 14526

References

Giguere T. A., Taylor G. J., Hawke B. R., abd Lucey P. G. (2000) The titanium contents of lunar mare basalts. Meteoritics & Planetary Science, 35, 193-200.