Lunar Meteorites: Northwest Africa 14681 and 16683
possible paired stones?
| from The Meteoritical Bulletin, No. 111 Northwest Africa 14681 (NWA 14681)(Northwestern Africa) 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. |
| from The Meteoritical Bulletin, No. 113 Northwest Africa 16683 (NWA 16683)Mali Lunar meteorite (troctolitic anorthosite) History: Purchased jointly by Ahmed Salek and Omar Bourki in Gadamis, Lybia from a nomad in Azwiker, Mali in December 2021. Physical Characteristics: (I. Malakhova, UAb) The two small fragments provided have medium greyish tan exteriors with many veinlets filled with creamy-brown colored material. Broken surfaces reveal a medium grey interior with lighter patches. Petrography: (C. Herd, and I. Malakhova, UAb) Optical and electron backscattered investigation of a polished thin section reveals a breccia dominated by creamy tan clasts in a brownish tan matrix, and numerous dark shock pockets and veins. Plagioclase is the dominant mineral, with clasts of pigeonite and olivine also present. No accessory minerals were identified. Tan to orange staining is present throughout. All mineral grains and clasts are recrystallized on a fine (<μm) scale, and pyroxene shows low pleochroism. Geochemistry: (C. Herd, A. Locock, D. Poon-Matsune, and I. Malakhova, UAb) Data obtained by EMP examination of carbon-coated thin section: low-Ca pyroxene: Fs27.1±1.43Wo11.1±1.5 (Fe/Mn = 52±4; n=9); olivine: Fa33.6±2.7 (Fe/Mn = 89±5; n=26); plagioclase: An97.3±0.8Or0.1±0.1 (n=31). Classification: Lunar meteorite (troctolitic anorthosite). May be paired with NWA 14681. Specimens: Type specimen of 20.6 g at UAb, main mass with Ahmed Salek and Omar Bourki. |
Randy Says… I have not studied these two meteorites. I put them on the same page so that it is easy to compare the descriptions. I have not found a photo of NWA 16683. |