Description
Northwest Africa 15364 (NWA 15364)
Algeria
Purchased: 2022 Feb
Classification: Martian meteorite (Nakhlite)
History: Purportedly found in Algeria and purchased by Mohammed Hmani in February 2022 from a Mauritanian dealer.
Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Igneous aggregate of compositionally-zoned, subhedral prismatic augite grains and anhedral olivine grains (exhibiting limited core to rim zoning) together with subordinate intermediate plagioclase and titanomagnetite (with ilmenite exsolution lamellae) plus accessory pyrrhotite and F-Cl-bearing apatite. Outer margins of augite grains contain orthopyroxene and pigeonite, and some augite occurs as stubby inclusions within olivine. Intercumulus regions contain fine grained, apparently hydrous “chlorophaeite” (red-brown in thin section), and similar material is present as thin veinlets within olivine grains.
Geochemistry: Zoned augite (Fs22.6-38.7Wo40.4-34.5, FeO/MnO = 33-38, N = 9), zoned olivine (Fa70.4-74.0, FeO/MnO = 48-52, N = 11), augite inclusions in olivine (Fs24.9-25.9Wo40.4-40.2, FeO/MnO = 33-35, N = 2), orthopyroxene (Fs45.9-66.3Wo0.7-4.8, FeO/MnO = 24-36, N = 9), pigeonite (Fs54.0-55.7Wo14.1-12.3, FeO/MnO = 33-35, N = 3), plagioclase (An35.6-37.7Or3.3-2.9, N = 4).
Classification: Martian (nakhlite).
Specimens: 21.8 g including one polished thin section at UWB
