NWA 1814


CBa, bencubbinite
standby for nwa 1814 photo
Found April 1999
no coordinates recorded

A single stone of 156 g was found in Morocco between Taouz and Ouzina by a French team under the organization of Bruno Fectay and Carine Bidaut. Analysis of this bencubbinite was conducted at the Museum National d'Histoire Naturelle, Paris, and it was described as being very similar to Bencubbin, Weatherford, and Gujba.

Large clasts of FeNi-metal constitute ~60 vol% of this bencubbinite, while the remainder is composed of olivine and pyroxene silicates having barred to crytocrystalline textures. A plagioclase mesostasis is also present. The metal clasts are composed primarily of kamacite with very rare troilite inclusions, and they exhibit oriented, roughly hemispheric shapes, possibly the result of quenching upon contact with the asteroid surface while still in a plastic state (Perron and Leroux, 2004). The best current evidence supports an origin for these late-formed metal-rich carbonaceous chondrites in an impact plume generated by a collision between planetary embryos (Krot et al., 2009). Following condensation of the various components, they were aerodynamically sorted according to their velocity, size, and density as they spread out into the nebular gas in a typical fan-shaped pattern. It was calculated by Morris et al. (2012) that in ~1% of the impacts the host planetesimal would travel in the direction of the impact plume, sweeping up some of the aerodynamically sorted ejecta within a short time period measured in weeks. They reason that this reaccreted material would have been mixed with existing crustal components to form a layer many meters thick. See the HaH 237 page for a more detailed scenario of the CB group formation process ascertained by Fedkin et al. (2015) through kinetic condensation modeling.

An analysis of N, C, and H in NWA 1814 revealed that the highest N abundances are located within tetrataenite mostly associated with sulfides and carbides, with high concentrations occupying metal grain boundaries (Perron and Mostefaoui, 2007). The N, C, and H isotopic values are consistent with those of Bencubbin. The specimen of NWA 1814 shown above is a 1.02 g partial end section. The main mass is shown in the top photo below, while a 23.5 g cut section is shown at the bottom, courtesy of the J. Piatek Collection.

standby for nwa 1814 photo
Photo courtesy of B. Fectay and C. Bidaut—meteorite.fr
standby for nwa 1814 photo
Photo courtesy of the J. Piatek Collection