from The Meteoritical Bulletin, No. 112
Northwest Africa 15806 (NWA 15806)
Lunar meteorite (feldspathic breccia)
History: The stone was found near Smara, Morocco. It was purchased from a dealer in Morocco.
Physical Characteristics: The stone (~15.0 × 15.0 × 10.0 cm) has a rugged surface with cm-sized vugs, dusted by desert soil, and no visible fusion crust. A cut surface exposes a fresh-looking interior. This polymict breccia includes a light grey matrix with numerous angular or more rounded white to light-gray lithic clasts.
Petrography: (R. Zhao, A. Bouvier, UBayr) The type specimen polished section consists of lithic clasts and mineral fragments within a clastic to glassy matrix. Melt rock clasts are generally rounded in shape and dominated by feldspathic (anorthitic), olivine-gabbro, troctolite and basalt lithologies. Mineral clasts vary in shape from angular to more rounded, and are dominated by anorthite, olivine, low-Ca pyroxene with exsolution lamellae, Ca-rich pyroxene, and minor ilmenite, chromite, Fe-S, Fe95.4Ni4.0Co0.3Cr0.3 metal.
Geochemistry: In host matrix, olivine is heterogeneous with Fa20.5±4.8 (Fe/Mn=81±13; n=16), or Fa46.2±12.6 (Fe/Mn=92±10; n=7). Pyroxene is Fe-rich augite with Fs52.4±14.2Wo30.5±4.7 (Fe/Mn = 64±5, n=4), low-Fe augite with Fs13.0±6.0Wo41.4±1.4 (Fe/Mn = 39±8, n=5), and orthopyroxene with Fs23.8±10.5Wo3.1±0.3 (Fe/Mn = 51±5, n=4). One pyroxene grain of pigeonite Fs48.2±1.4Wo4.7±1.0 (Fe/Mn = 55±1, n=3) has up to μm-wide augite exsolution lamellae Fs30.6±4.4Wo28.6±7.1 (Fe/Mn = 54±4, n=4). An anorthositic clast contains anorthite An97.0±0.3 (Or = 0.1±0.1, n=10) with orthopyroxene inclusions Fs38.0±0.1Wo2.7±0.2 (Fe/Mn = 65±2, n=2). A clast of troctolite contains olivine Fa17.8±0.1 (Fe/Mn = 83±6, n=10) and anorthite An96.5±0.4 (Or= 0.1±0.1, n=9).
Classification: Lunar (polymict fragmental breccia).
Specimens: 22.9 g including a polished mount and a thin section at UBayr. 40 g were deposited with the Ministry of Mines in Morocco (catalogue # 106). Main mass with Achim and Moritz Karl.
I have not studied Northwest Africa 15806.
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