Northwest Africa 13460 (NWA 13460)

South, Morocco

Find: 2017

Classification: Martian meteorite (Shergottite)

History: The meteorite was purchased in Tucson, USA by Zhouping Guo.

Physical characteristics: The shape of the meteorite is irregular. There is black fusion crust partly covering its surface. The interior is generally grey. Glassy maskelynite and a small amount of black glass pockets can be observed.

Petrography: Petrology (Z.Xia, B.Miao, Q.Deng, GUT):The meteorite has a diabasic structure, which is mainly composed of pigeonite(~50 vol%), augite(~15 vol%), maskelynite(~25 vol%) and accessory minerals(~10 vol%). The accessory minerals are mainly composed of chromite, Fe-Ti oxide, troilite, vesicular glass and phosphate. Pigeonite and augite (typical size 0.1-1.6mm) are automorphic in the form of slab columns, and obvious component zoning can be observed. The meteorite experienced a strong impact metamorphism, which caused the plagioclases to be completely transformed into maskelynites, and pyroxenes and maskelynites were relatively broken.

Geochemistry (Z.Xia, B.Miao, Q.Deng, GUT): Pyroxenes show two compositional trends: pigeonite (En_31.2-55.7Fs_32.2-55.8Wo_10.2-14.3, average En_42.9Fs_44.5Wo_12.6, FeO/MnO=34.2-4.4, n=9) and augite (En_23.6-45.8Fs_26.6-60.5Wo_15.8-31.7, average En_34.5Fs_40.9Wo_24.6;FeO/MnO=32.0-3.3, n=5). Maskelynite (An_39.8-45.8Ab_51.2-55.7Or_2.7-4.6, average An_43.2Ab_53.4Or_3.4, n=9).

Classification: Martian (basaltic shergottite)

Specimens: A polished section and 1.78 g sample are stored in the Institution of Meteorites and Planetary Materials Research of GUT.