Northwest Africa 4294

Morocco or Algeria

Find: February 2006

Ordinary chondrite (type 3)

History: Purchased from a Moroccan dealer at the Tucson Gem and Mineral Show by A. Hupé in February 2006.

Physical characteristics: A single 84.2 g light brown stone lacking fusion crust and with abundant, large chondrules.

Petrography: (A. Irving and S. Kuehner, UWS): Closely packed PO and POP chondrules with a mean diameter 1.2 mm.Chondrules contain accessory phases including Cr-bearing clinopyroxene, chromite, partially altered kamacite, taenite, troilite and terrestrial barite. The content of metal (+ minor Fe hydroxide) is very low (mode determined by BSE imaging of a whole thin section is 3 vol%).

Geochemistry: Olivine (mostly Fa_2-25, with rim compositions up to Fa₉₅) Oxygen Isotopes: (D. Rumble, CIW) Analyses of two acid-washed whole rock fragments by laser fluorination gave, respectively, δ¹⁸O = 5.38, 5.31; δ¹⁷O = 3.34, 3.23; Δ¹⁷O = 0.508, 0.443 (all ‰). These oxygen isotopic compositions are closer to the TFL than to those of H chondrites and far removed from those of LL chondrites.

Classification: Ordinary chondrite (type 3); S1, W2.

Specimens: A total of 22 g of sample and one polished thin section are on deposit at UWS. AHupé holds the main mass.