Northwest Africa 14607 (NWA 14607)

Algeria

Find: 2021

Classification: Martian meteorite (Shergottite)

History: Purchased by Matthew Stream from Bashir Saleck in 2022. Two identically appearing stones (621.7 + 194.6 g) were found together near Adrar, Algeria, in January 2021.

Physical characteristics: Dark brown, sandblasted exterior with remnants of fusion crust. Fresh chipped surface reveals the presence of shiny macroscopic maskelynite.

Petrography: (A. Ross and C. Agee, UNM) The two major phases in this meteorite are clinopyroxene and maskelynite. Ubiquitous minor phases are merrillite, apatite, titanomagnetite, ilmenite and troilite. The clinopyroxene has a modal abundance of approximately 65%, with significant core to rim zoning indicating an igneous crystallization trend with compositional zoning trends with sub-calcic augite and ferro-pigeonite clusters, Mg-rich orthopyroxene and Mg-Rich pigeonite compositions are absent. Clinopyroxene average grain size is approximately 300-500 μm. Maskelynite has modal abundance of approximately 25%, most grains are thin and elongate with maximum length ~1 mm. Silica-rich melt inclusions observed in maskelynite. Trace fayalite was detected.

Geochemistry: (A. Ross and C. Agee, UNM) Clinopyroxene (all) Fs_49.8±24.1Wo_22.3±8.5. Fe/Mn=35±6, n=20; sub-calcic augite Fs_25.9Wo_32.3±2.3, Fe/Mn=30±3, n=7; ferro-pigeonite Fs_74.9±4.3Wo_15.2±2.4, Fe/Mn=41±2, n=9; maskelynite An_48.4±4.7Ab_47.8±3.7Or_3.8±1.0, n=6; silica-rich inclusions SiO₂=79.1±1.2, Al₂O₃=12.0±1.4, CaO=1.2±0.3, Na₂O=3.6±0.4, K₂O=1.9±0.6 (wt%), n=2; fayalite Fa_94.2, Fe/Mn=61.

Classification: Evolved pyroxene-phyric shergottite basalt.

Specimens: 20 g plus a probe mount on deposit at UNM, Matthew Stream holds the main masses.