Northwest Africa 14542 (NWA 14542)

(Northwest Africa)

Purchased: 2021 Aug

Classification: Rumuruti chondrite (R3)

Physical characteristics: Crusted stone. Cut surface reveals a dark interior with grayish chondrules set in an abundant dark matrix.

Petrography: (J. Gattacceca, CEREGE) Brecciated chondrite with well-delineated chondrules, mostly porphyritic type and less commonly radial pyroxne and barred olivine types, with apparent diameter 530±240 µm (n=31) set in an abundant iron-rich fine grained matrix (68 vol% by point counting, n=248). Sulfides, both troilite and pentlandite, are abundant in the matrix where they form spherical grains to 500 µm, in chondrules, and around chondrule rims (5 vol% by point counting, n=248). Magnetite is less abundant and associated with sulfides. No metal was observed. No CAI was observed.

Geochemistry: Olivine Fa_31.6±9.7, range Fa_14.7-42.7, FeO/MnO 82.9±27.2, Cr₂O₃ 0.30±0.42 wt%, NiO 0.18±0.13 wt%(n=15). Matrix olivine Fa_51.5 (n=1). Low-Ca pyroxene Fs_15.1±7.7Wo_1.0±0.6 (n=4). Magnetite Cr₂O₃ 0.86 wt% (n=2). Defocused matrix FeO 42.3 wt%, analytical total 100.3 wt%.

Classification: Rumuruti chondrite (R3)

Specimens: Type specimen at CEREGE, main mass with Pierre-Marie Pelé.