Northwest Africa 7034


Northwest Africa 7034 is a Martian meteorite believed to be the second oldest yet discovered. It is estimated to be two billion years old and contains the most water of any Martian meteorite found on Earth. Although it is from Mars it does not fit into any of the three SNC meteorite categories, and forms a new Martian meteorite group named "Martian ". Nicknamed "Black Beauty", it was purchased in Morocco and a slice of it was donated to the University of New Mexico by its American owner.

Discovery and naming

The meteorite was found in the Sahara Desert in 2011 and was purchased in Morocco by a meteorite dealer who sold it to a collector in the United States. For this reason the exact geographic coordinates of the find location are unknown, and there is a strong possibility that meteorites reported to have been found in Morocco were, in fact, not. Like all meteorites that are found in large numbers or sold at markets the name stands for the geographic region and a number, which is given out consecutively. NWA 7034 carries the nickname "Black Beauty".

Description

The meteorite contains components as old as 4.42 ± 0.07 Ga, and was heated during the Amazonian period of Mars. It is the second oldest Martian meteorite known.

Classification

NWA 7034 is the first Martian meteorite that is a breccia and does not fall in any of the known Martian meteorite groups. NWA 7034 was classified as an ungrouped planetary achondrite until the Meteoritical Society approved the new designation "Martian " in January 2013. The iron/manganese ratio is consistent with that of other Martian meteorites, but the oxygen isotopes do not correlate with a Martian origin. The change in oxygen isotope ratios could be explained by removal or addition of heavier or lighter isotopes, or by mixing with a mass with a different isotopic ratio. This could happen during aqueous alteration of the Martian crust. Another explanation would be an isotopic contamination of the Martian crust during impact brecciation.
If it were a terrestrial rock it would be classified as a regolith breccia.

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