|from The Meteoritical Bulletin, No. 109
Northwest Africa 13582 (NWA 13582)
Classification: Lunar meteorite (feldspathic breccia)
History: Purchased by Bo Zhang in Jun. 2019 from an anonymous dealer.
Physical characteristics: Small vesicles are visible in the hand specimen.
Petrography: Lithic clasts and mineral fragments (0.01 to 2 mm) set in an anorthositic matrix. Lithic clasts include anorthositic, gabbroic, noritic and impact melted clasts. Mineral fragments are dominated by pyroxene and minor olivine. Plagiocalse is highly Ca-rich (K2O < 0.025 wt%) while a few clasts contain relatively K-rich plagiocalse (K2O = 0.23-0.45 wt%). Some pyroxene grains exhibit exsolved lamella. Vesicles are common. Other accessory minerals include ilmenite, troilite and FeNi metal.
Geochemistry: Mineral compositions and geochemistry: (M. Hutson, A. Ruzicka, Cascadia; K. Ziegler, UNM): Oxygen isotopes on acid treated samples in per mil, relative to V-SMOW linearized values): δ17O’ = 3.083±0.031, δ18O’ = 5.933±.052, Δ17O’ = -0.050±.005 (N=3). Plagioclase compositions of clasts are variable, but the range of compositions in the two lithologies overlap. Lithology 1 clasts: An87-96Or0.7-1.5 (N=18, 2 clasts); Lithology 2 clasts: An89-95Or0.7-1.1 (N=21, 3 clasts). Matrix plagioclase for the two lithologies is also similar. Lithology 1 matrix: An91.3±2.3Or0.9±0.6 (N=23); Lithology 2 matrix: An92.7±2.2Or0.9±0.9 (N=27). Matrix pigeonite (Wo5-20) and olivine grains are more magnesian in lithology 1 than in lithology 2. Lithology 1 matrix pigeonite: Fs29.9±3.1, Mg# = 67.9±3.2 (N=17); Lithology 2 matrix pigeonite: Fs31.7±1.9, Mg# = 64.2±1.1 (N=13); Lithology 1 matrix olivine: Fa39.8±2.2, Mg# = 60.2±2.1 (N=11); Lithology 2 matrix olivine: Fa43.4±0.9, Mg# = 56.5±0.9 (N=15).
Classification: Plagioclase (An95.5-99.3Or0-0.2, n=14; An85.0-90.7Or1.6-3.5, n=3), olivine (Fa19.6-34.9, FeO/MnO=83.3-98.2, n=7), low-Ca pyroxene (Fs16.5-47.8Wo2.4-13.2, FeO/MnO=48.2-62.7, n=11), Ca-rich pyroxene (Fs8.8-52.8Wo27.2-44.3, FeO/MnO=43.6-73.4, n=11).
Specimens: The texture and mineral composition are consistent with lunar feldspathic breccias.
I have not studied 13582. It might be another NWA 8046 pair.
Meteoritical Bulletin Database