NWA 4901 Stone meteorite, achondrite, ungrouped basalt, photos, pictures, images

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NWA 4901
Stone, achondrite, ungrouped basalt
(NWA 011 pairing group)
Erfoud, Morocco, purchased 2007
TKW: 24g, (NWA 011 pairing group TKW: 950g)

8.90g endcut of the ungrouped basaltic achondrite NWA 4901. This rock represents one of the rarest meteorite lithologies ever discovered in history. It is paired with NWA 011 (40g), NWA 2400 (137g), NWA 2976 (219g) and NWA 4587 (530g), which adds to a total TWK of just 950g for this pairing grouplet since 1999. Despite more than 50 scientific papers dealing with every aspect of composition, genesis and origin of the material, many aspects of its morphogenesis remain a mystery until present. Palme and other researchers suggested the planet Mercury as a possible origin, Floss et Al. proposed basaltic asteroid 1459 Magnya as a possible mother body of NWA 011 and its pairings.

The meteorite consists mainly of pigeonite and plagioclase, with minor amounts of opaque silica and phosphate minerals. It resembles noncumulate eucrites on the basis of texture, mineralogy, and certain chemistry. But there are major differences in terms of its anomalous O-isotopic compositions and its higher Fe/Mn values. Therefore the NWA 011 pairings represent a new type of achondritic basaltic meteorite, with no apparent genetic relationship with the Vesta eucrites. There is strong evidence that the parent body of the NWA 011 pairings has formed in a different region of solar nebula than that of the HED parent body. Measured by the flux of material to earth for this specific type of meteorite it originates in a very distant region of the asteroid belt, provided the mother body is indeed an asteroid. For example the flux of material for Mercury has been calculated as ~1% of that from Mars.

The crystal pattern of the cut surface pictured appears as a mesh of anthracite polygons on a fine grained curry colored matrix. Uniformity and even distribution of the pattern resembles the skin of a cheetah.

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