Lunar Meteorite: Adrar 012

from The Meteoritical Bulletin, No. 112

Adrar 012

Adrar, Algeria
Find: 2021 November
Mass: 941.3 g (57 pieces)

Lunar meteorite (feldspathic breccia)

Physical Characteristics: Stones have a gray patina. Interior shows various lithologies of abundant millimeter-sized clasts which are cemented within a gray matrix.

Petrography: (R. Zhao, A. Bouvier, UBayr) The type specimen polished section consists of millimeter-sized melt rock clasts, sub-millimeter-sized glassy spherules, and lithic mineral fragments within a clastic to glassy matrix. Melt rock clasts are generally rounded in shape and dominated by feldsphatic (anorthitic) and basalt lithologies. Mineral clasts are angular to more rounded in shape dominated by anorthite, olivine, low-Ca pyroxene with exsolution lamellae, Ca-rich pyroxene, and minor chromite, ilmenite, Fe-S and Fe-Ni metal.

Geochemistry: In the host matrix, olivines are heterogeneous with Fa26.3±1.7 (Fe/Mn=98±3; n=2), Fa37.3±0.1 (Fe/Mn=106±6; n=3), or Fa73.6±1.7 (Fe/Mn=98±3; n=2), pyroxenes are Fe-rich augite with Fs47.4±2.9Wo30.5±3.2 (Fe/Mn = 62±1, n=2), low-Fe augite with Fs19.2±2.2Wo40.9±2.4 (Fe/Mn = 49±5, n=2), pigeonite with Fs40.2±2.1Wo 12.7±1.5 (Fe/Mn = 57±1, n=2), orthopyroxene with Fs48.1±0.1Wo2.1±0.1 (Fe/Mn = 55±3, n=2) and plagioclase is An95.9±0.5 (Ab= 2.0±0.2, n=4). In a basaltic clast, subhedral poikilitic low-Ca pyroxene Fs21.3±0.7Wo10.1±2.4 (Fe/Mn =50±5, n= 14) is enclosed within plagioclase An94.5±0.9 (Ab= 4.8±0.7, n = 14) and associated with glassy mesostasis, ilmenite, FeS and metal as Fe92.0Ni7.4Co0.5. In a feldspathic clast, anorthite An94.7±1.0 (Ab= 2.7±0.5, n = 10), associated with quenched glass, metal Fe91.7Ni7.9Co0.4 and FeS. Oxygen isotopic analyses (R. Greenwood, J. Malley, OU) δ17O=3.349±0.019, δ18O=6.391±0.042, Δ17O=0.025±0.003 (n=2), analyses after leaching ~100 mg sample powders in ethanolamine thioglycollate (EATG).

Classification: Lunar (feldspathic regolith breccia.

Specimens: 28.4 g including a polished mount at UBayr. Main mass with Stone gallery (The Netherlands).

Randy Says…

I have not studied Adrar 012.

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Adrar 012