Northwest Africa 15910 (NWA 15910)

(Northwest Africa)

Purchased: 2023

Classification: Martian meteorite (Shergottite)

History: Two identically appearing stones 276.6 and 85.3 g were found together. The 85.3 g stone was purchased from Mark Lyon by Jiong Ge in 2023.

Physical characteristics: Sandblasted exterior lacking fusion crust.

Petrography: (C. Agee and A. Ross UNM) The two major phases in this meteorite are clinopyroxene and maskelynite. Ubiquitous minor phases are magnetite, titanomagnetite, ilmenite, merrillite, troilite, and fayalite. The clinopyroxene has a modal abundance of approximately 60%, with significant core to rim zoning observed in backscatter electron images indicating an igneous crystallization trend with Mg-rich pigeonite cores, mantled by augite, and rimmed with ferropigeonite. Clinopyroxene average grain size is approximately 300-500 μm. Maskelynite has modal abundance of approximately 30%, most grains are thin and elongate with maximum length ~1 mm.

Geochemistry: (A. Ross, UNM) Clinopyroxene Fs_54.7±19.5Wo_17.4±6.0, Fe/Mn=36±5, n=12; maskelynite An_50.6±4.8Ab_47.9±4.3Or_1.5±0.5, n=6; fayalite Fa_97.2±1.0, Fe/Mn=55±6, n=4.

Classification: Evolved pyroxene-phyric basalt, clinopyroxene compositional zoning trends are similar to QUE 94201, NWA 12522, NWA 12550, NWA 12960, and Ben Kesbes 002, however this meteorite also has minor amounts of fayalitic olivine present.

Specimens: 20 g on deposit at UNM, Jiong Ge holds one stone of 85.3 g.