Northwest Africa 10324 (NWA 10324)

Morocco

Purchased: 2015 Mar 10

Classification: Carbonaceous chondrite (CR2)

History: Purchased in Erfoud, Morocco, on 2015 March 3.

Physical characteristics: One partly oriented stone with desert varnish weighing 141.6 g.

Petrography: (C. R. Heckel and J. Zipfel, Senck) Two polished sections show a texture of 50-60% chondrules and 30-35% fine-grained matrix. Chondrules range in size from 0.7 to 1.5 mm. They are dominated by type I PO and POP chondrules. Type II chondrules of PO and BO textures are rare. Some chondrules contain clear mesostasis. Up to 10% FeNi is present as rims around or as blebs within type I chondrules. Rare large metal rims also contain chromite inclusions and networks of troilite veins. Sulfide is predominantly present in the fine-grained matrix. Pervasive veins of metal and troilite are almost completely replaced by Fe-oxides.

Geochemistry: Mineral compositions and Geochemistry: EMPA data of Type I chondrules: olivine cores Fa_3.3±1.3, N=24, olivine rims Fa_1.7-20.7, N=17, low Ca-pyroxene Fs_2.9±0.9Wo_0.7±0.2, N=23, high Ca-pyroxene Fs_2.2±1.0Wo_43.5±2.6, N=7, mesostasis SiO₂=45-55, Al₂O₃=16-33; CaO=11-19 (all in wt.%). Type II chondrules: olivine cores Fa_16.7±2.5, N=9, olivine rims Fa_33.7±3.3, N=6, mesostasis SiO₂=65-67, Al₂O₃=15-17; CaO=4-5 (all in wt. %). Oxygen isotopes: (A. Pack, UGött) Analyses by laser fluorination gave: δ¹⁷O = 1.79, δ¹⁸O = 5.95, Δ¹⁷O = -1.37 (all per mil) and plot in the CR field.

Classification: Carbonaceous chondrites (CR2), low shock and moderate weathering levels.

Specimens: A total of 21 g is on deposit at Senck. The main mass holder is anonymous.