Northwest Africa 8560 (NWA 8560)

(Northwest Africa)

Purchased: 2013

Classification: Ordinary chondrite (H5, melt breccia)

History: Purchased by Brahim Tahiri from a Moroccan hunter and sent to his partner Sean Tutorow for classification, April, 2013.

Physical characteristics: Single stone, weathered exterior. Saw cut reveals very fine-grained, dark-gray shock melt with rafted angular fragments of chondrite material up to 1 cm.

Petrography: (C. Agee, UNM) Microprobe examination of a polished mount shows domains of quench shock melt with islands of ordinary chondrite clasts with some equilibrated chondrules, plagioclase grains <50 μm, FeNi metal, troilite, Fe-oxide, chromite.

Geochemistry: (C. Agee and N. Muttik, UNM) Olivine Fa_19.1±0.8, Fe/Mn=40±2, n=11; low-Ca pyroxene Fs_16.9±0.9Wo_1.9±0.3, Fe/Mn=24±2, n=10; shock melt (20 μm electron microprobe beam) SiO₂=47.73±1.71, TiO₂=0.14±0.03, Al₂O₃=3.76±1.01, Cr₂O₃=0.54±0.11, MgO=28.16±2.17, MnO=0.38±0.03, FeO=12.78±0.30, CaO=2.28±0.72, Na₂O=1.67±0.50, K₂O=0.22±0.06 (all wt%), n=8.

Classification: H5-melt breccia, weathering grade W2.

Specimens: 20.1 g including a probe mount on deposit at UNM, Sean Tutorow holds the main mass.