Northwest Africa 10917 (NWA 10917)

Morocco

Purchased: 2015 Oct

Classification: Rumuruti chondrite (R3)

History: Purchased by S. Arnold (of Chicago, Illinois) in October 2015 from Aziz Habibi. Subsequently sold to the owner in the same month. Likely recovered shortly before initial sale.

Physical characteristics: A single stone partially covered in a glossy, dark brown fusion crust. Saw cut reveals chondrules and clasts of variable size (up to ~2 mm) in a red-brown to grey matrix.

Petrography: (C. Herd, UAb) Microprobe and petrographic examination of thin section shows numerous chondrules in the range 150-1400 μm (most ~200-600 μm) comprising ~75% of mode (estimated). Fe-Ni sulfide and magnetite also observed. The rock does not appear to be brecciated.

Geochemistry: (C. Herd and S. Kampel, UAb) All olivine Fa_39.3±6.1 (n=59); chondrule olivine Fa_34.6±9.6, range Fa_1.3-41.5 (n=18), matrix olivine Fa_41.4±0.7 (n=41); low-Ca pyroxene Fs_11.9±2.9, Wo_0.5±0.2 (n=3); high-Ca pyroxene Fs_10.8±1.4, Wo_46.3±1.3 (n=7), plagioclase An_6-17Or_4-9 (n=4).

Classification: R3 chondrite, suggested sub-type 3.8, based on range of chondrule mineral compositions, and olivine-rich matrix. Range of chondrule sizes comparable to other R chondrites (e.g., Hammadah al Hamra 119; see Bischoff et al., 2011).

Specimens: A 6.8 g specimen, including one thin section, is at UAb. Main mass is with the owner.