polymict diogenite
Purchased October 2002
no coordinates recorded
A single, fusion-crusted stone weighing 803 g was purchased in Morocco by A. and G. Hupé. The meteorite was designated NWA 1648 and classified at the University of Washington as a rare polymict diogenite. This brecciated diogenite comprises a variety of mineral and lithic clasts, primarily low-Ca orthopyroxene, but also including a small number of cumulate and basaltic eucrite clasts and quenched glass, along with minor amounts of anorthite, silica, ilmenite, troilite, and breakdown products of former pyroxferroite.
Northwest Africa 1648 contains a large component of orthopyroxene clasts (>80 vol%) that exhibits a wide compositional variation as reflected by a wide range of Fe/Mg ratios (= Fa ÷ [100 – Fa]); the Fa value is 28.2–34.8. This range is consistent with the theory that diogenites are orthopyroxene cumulates resulting from fractional crystallization in a number of compositionally distinct basaltic magma sources.
Additional details about the polymict diogenite group can be found on the NWA 1239 page. The photo of NWA 1648 shown above is a 1.02 g partial slice. The photo below allows a high-resolution view of a large slice of NWA 1648 in the R. A. Langheinrich Collection.
