Northwest Africa 4677

Northwest Africa

Find: July 2006

Achondrite (eucrite, monomict)

History: F. Béroud purchased the meteorite in July 2006 at Ste Marie-aux-Mines, France. According to the Moroccan seller, the meteorite was found in the Sahara and other pieces had been previously sold.

Physical characteristics: A single, complete, partially crusted stone weighing 156.4 g.

Petrography: (A. Seddiki, Ud'OEA and UJM; B. Moine, J.Y. Cottin, UJM; B. Devouard, UBP and M. Denise, MNHNP). The rock is brecciated and transected by impact melt veins. Undeformed clasts mostly consist of pyroxene and plagioclase grains (1-4 mm) with a cumulative texture. The pyroxenes are pigeonites with very fine (<1μm) exsolution lamellae. These clasts are embedded in a finer grained clastic matrix of the same nature. Accessory phases include spinel and taenite-kamacite-troilite assemblages and silica.

Mineral compositions and geochemistry: Spinel (Fe,Ti-rich chromite, Cr₂O₃ = 45 wt%), plagioclase (An₉₁), pigeonite (Fs_41.20-42.40Wo_7-10), pyroxene (Fe/Mn = 27-32). Kamacite (Ni = 4.9) and taenite (Ni = 38.5-44.6, both wt%).

Classification: Achondrite (eucrite, monomict); S3, minimal weathering. The meteorite is similar to Dhofar 007 and EET 92023.

Type specimens: A type specimen of 20.2 g is on deposit at MNHNP and two sections are kept at UBP. Béroud hold the main mass.