Lunar Meteorite: Northwest Africa 12971 and 14681

possible pairs?

A slice of Northwest Africa 12971. Photo credit: Craig Zlimen
Two slices of NWA 12971. Photo credit: Matthew Stream
Two sides of a 4.8-g slice of Northwest Africa 14681 (polished on left, unpolished on right). Photo credit: Matthew Stream

from The Meteoritical Bulletin, no. 108

Northwest Africa 12971 (NWA 12971)

(Northwest Africa)
Purchased: 2019 April
Mass: 270 g (1 piece)

Classification: Lunar (troctolitic melt rock)

History: Purchased jointly by Craig Zlimen, Mark Lyon and Matthew Stream in April 2019 from a Moroccan dealer.

Physical characteristics: A single light gray stone (280 g) with visible vesicles and light brown weathering products on one side. The fresh interior is composed predominantly of vesicular melt rock which contains some clast-like regions of coarser grained melt rock.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Very fine-grained (grainsize up to 5 µm), microvesicular melt-textured specimen composed predominantly of anorthite plus subordinate olivine and accessory pigeonite, augite, chromite (exhibiting zoning from Ti-bearing cores to Ti-free rims), troilite and pyrrhotite. No intact clasts were observed anywhere in the entire 5 cm diameter slice examined by microprobe imaging, but there are sporadic coarser-grained (up to 40 µm) melt-textured regions.

Geochemistry: Anorthite (An97.2-97.7Or0.0, N = 2), olivine (Fa24.9-35.5, FeO/MnO = 77-99, N = 6), magnesian olivine core (Fa19.0, FeO/MnO = 98), ferroan olivine rim (Fa38.3, FeO/MnO = 80), pigeonite (Fs26.2Wo19.4, FeO/MnO = 44), augite (Fs19.8-35.1Wo35.5±0.0, FeO/MnO = 43-55, N =2).

Classification: Lunar (troctolitic melt rock). The predominance of anorthite and olivine indicates a troctolitic bulk composition. The texture and apparent absence of clasts are consistent with crystallization from a totally molten state.

Specimens: 22.3 g in the form of a large polished slice at UWB; remainder with Mr. C. Zlimen, Mr. M. Lyon and Mr. M. Stream.

from The Meteoritical Bulletin, No. 111

Northwest Africa 14681 (NWA 14681)

(Northwestern Africa)
Purchased: 2021
Mass: 4.9 kg (1 piece)

Lunar meteorite (troctolitic anorthosite)

History: Purchased from a Moroccan meteorite dealer in 2021.

Physical Characteristics: Desert weathered exterior. Sawcut surfaces show a breccia with light gray and dark gray clasts. Reflected light microscopy reveals abundant small vesicles throughout.

Petrography: (C. Agee, UNM) This meteorite is a troctolitic anorthosite (Prinz and Keil, 1977) with plagioclase (~85%), olivine (~10%), and pigeonite (~1%). Minor phases include troilite and chromite. Metal was not detected.

Geochemistry: (A. Ross, UNM) Plagioclase An96.4±1.5Ab3.5±1.5Or0.2±0.1, n=8; olivine Fa23.8±5.6, Fe/Mn=89±5, n=12; pigeonite Fs23.4±1.1Wo15.6±3.9, Fe/Mn=48±6, n=6.

Classification: Lunar (troctolitic anorthosite) based on Stoeffler et al. (1980).

Specimens: 50.1 g on deposit at UNM, Mark Lyon holds the main mass.

Randy Says…

I have not studied Northwest Africa NWA 12971 and 14681. The description are similar as are their textures in the photographs, so they may be paired.

More Information

Meteoritical Bulletin Database

NWA 12971 | 14681