Northwest Africa 10456 (NWA 10456)

(Northwest Africa)

Purchased: Feb 2002

Classification: Ordinary chondrite (L4)

History: Purchased from a Moroccan trader at the Tucson show in February 2002; 22.2 g slice donated to Cascadia on July 2, 2012.

Physical characteristics: Fusion crust covers ~90% of the surface; all exterior surfaces show brown-red weathering patina; cut faces show chondritic texture.

Petrography: Composed of well-defined chondrules (diameter 0.73±0.41 mm, N=77), some with fine-grained rims, and ~20% intervening opaque to translucent fine-grained matrix. Contains ~2-3% metal + troilite each, with ~40-50% metal and ~40% troilite weathered. Shock stage S4 (N=25 olivine grains). One ~2 × 1 mm inclusion, an apparent clast, contains chondrule and silicate fragments and a spinel-rich micro-CAI (~60 μm across) embedded in troilite.

Geochemistry: (M. Ream and A. Ruzicka, Cascadia) Olivine (Fa_24.2±0.4, N=30), low-Ca pyroxene (Fs_15.2±5.7Wo_1.4±1.8En_83.4±6.0, N=19).

Classification: L4 chondrite based on texture and mineral chemistry.

Specimens: Cascadia holds a 19.6 g slice, a polished thin section, and a mounted butt. Bob Falls holds the main mass.