Northwest Africa 16003 (NWA 16003)

(Northwest Africa)   Purchased: 2023 Jan

Classification: Carbonaceous chondrite (CK3)

History: Purchased by Jaouad Chaoui in January 2023 from an Algerian dealer.

Petrography:  Well-defined unequilibrated chondrules (some with multiple rims, apparent diameter 1000±550 µm, N = 26) containing Cr-bearing magnetite, together with irregularly-shaped, very fine-grained polymineralic objects and very rare CAIs, are set in a fine grained recrystallized matrix (~25 vol.%, brown in thin section) containing Cr-bearing magnetite and pentlandite. One small CAI consists of anorthite, diopside, spinel and magnesian olivine. The unusual polymineralic objects (up to 3.5 mm in maximum dimension) are relatively abundant and mineralogically complex. Two examples (designated A and B) were examined in detail. Object A has a CAI-like texture, is composed predominantly of relatively sodic plagioclase (oligoclase), Fe-rich olivine and strongly-zoned clinopyroxene, and appears to contain submicron "wormy", possibly multiphase components. Object B is olivine-free and composed of relatively sodic plagioclase (oligoclase), diopside, Al-rich clinopyroxene, strongly-zoned clinopyroxene and rare ilmenite, and also appears to contain submicron "wormy", possibly multiphase components.

Classification: Carbonaceous chondrite (CK3). The Cr2O3 contents of magnetites are intermediate between the accepted ranges for CVox3 chondrites and CK3 chondrites. The presence of unusual polymineralic clasts not present in either of those meteorite groups is noteworthy.