Northwest Africa 13459 (NWA 13459)

South, Morocco

Find: 2017

Classification: Martian meteorite (Shergottite)

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

Physical characteristics: The meteorite is irregular in shape. Most of the surface of the meteorite is covered with black fusion crust. The interior is grayish brown with clear, glassy maskelynite grains, and sporadically-distributed dark glass shock pockets.

Petrography: Petrology (Z.Xia, B.Miao, Q.Deng, GUT): The meteorite has a fine-grained basaltic texture, which is mainly composed of pyroxene and maskelynite. The accessory minerals are chromite, Fe-Ti oxide, troilite, vesicular glass and phosphate. Pyroxene is an idiomorphic crystal in the form of prisms, which is composed of highly fractured pigeonite and augite, with a particle size of 0.2-2mm, and obvious chemical zoning can be observed. The maskelynite is relatively broken. Plagioclase is completely transformed into maskelynite.

Geochemistry (Z.Xia, B.Miao, Q.Deng, GUT): Pyroxenes show two compositional trends: pigeonite (En_27.5-58.7Fs_29.6-59.0Wo_9.2-13.6, average En_43.3Fs_44.6Wo_12.1, FeO/MnO=35.3; 4.6, n=6) and augite (En_28.0-45.0Fs_22.8-55.4Wo_16.6-33.3; average En_38.7Fs_33.7Wo_27.6; FeO/MnO=31.6-3.7, n=4). Maskelynite (An_42.3-48.0Ab_50.0-54.7Or_1.8-3.0, average An_46.1Ab_51.7Or_2.2, n=5).

Classification: Martian (basaltic shergottite)

Specimens: A polished section and about 6.5 g sample are stored in the Institution of Meteorites and Planetary Materials Research of GUT, the main mass is exhibited in the Geological Museum of Guilin.