Lunar Meteorite: Bir Moghrein 003

from The Meteoritical Bulletin, No. 112

Bir Moghrein 003 (BiG 003)

Tiris Zemmour, Mauritania
Purchased: 2023
Mass: 1400 g (many pieces)

Lunar meteorite (melt breccia)

Petrography: (K. Metzler, IfP) Achondritic clast-rich melt rock, consisting of lithic clasts (up to several cm) and mineral fragments (plagioclase, olivine, exsolved pyroxene) set in a fine-grained crystallized melt. A heavily shocked olivine-gabbro clast with a size of ~2.5 cm was found. The crystallized melt is dominated by plagioclase, with smaller amounts of olivine and pyroxene. Accessories are Cr-Al-spinel, ilmenite, and Ni-bearing metal.

Geochemistry: Mineral compositions and geochemistry: Mean olivine composition: Fa_14.8±0.6 (Fa_13.9-15.9); Fe/Mn (at.): 92; n=9. Mean composition of low-Ca pyroxene (host): Fs_15.5±2.8Wo_2.6±0.7 (Fs_12.2-18.2Wo_1.9-3.7); Fe/Mn (at.): 51; n=5. Mean composition of Ca-rich pyroxene (exsolution lamellae): Fs_8.3±1.8Wo_42.5±1.5 (Fs_5.4-10.8Wo_40.8-45.1); n=7. Mean plagioclase composition: An_95.9±1.4Or_0.0±0.1 (An_93.1-97.0Or_0.0-0.3); n=7.

Classification: Lunar melt breccia, based on texture, mean Fe/Mn value in olivine, and high An values in plagioclase.

Specimens: Largest piece: ~400 g. 20 g at Institut für Planetologie, main mass with Said Muftah Bachir

Randy Says…

I have not studied Bir Moghrein 003.

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Bir Moghrein 003