Northwest Africa 4801 meteorite (NWA 4801), Northwest Africa Meteoritesi

Regional Level Types
Northwest Africa 4801 meteorite (NWA 4801)	Meteorite Fall Location
Northwest Africa Meteorites	Group of Meteorite Fall Locations

Plutonic angrite (achondrite)
Find, 2007; 252 g


The Northwest Africa 4801 (NWA 4801) was found in 2007 as a single, but friable stone which broke int0 4 pieces. Clinopyroxene and pure anorthite are most prominent, but olivine, pleonaste, merrillite and minor troilite are also found. Early forming olivine is enclosed by clinopyroxene which is in turn surrounded by the anorthite and merrillite. The Ca-rich olivine, anorthite, and Al-Ti rich clinopyroxene are markers of the rather rare angrite class with its various Ca-Al-Ti-rich phases and other chemical signatures. Angrites are also ancient rocks with somewhat distinguishable crystallization ages of ~4.56 billion years. NWA 4801 is a little unusual among the angrites as it both lacks kirschsteinite (usually found in angrites) and is significantly richer in merrillite than other angrites. This may be due to its formation in a somewhat deeper and hotter initial magmatic environment than most other angrites. Minor amounts of kamacite — found in some but not all angrites — shows signs of weathering.

The terminology for NWA 4801’s Al,Ti-rich clinopyroxene varies somewhat in the references cited here and in the literature. Some authors prefer the terms ‘Fassaite’ and ‘Diopside’ but there seems to be no clear consensus.

Other Regions, Features and Areas containing this locality

References