Martian meteorite
NWA 7034 is the first Martian meteorite that is a breccia and does not fall in any of the known Martian meteorite groups (shergottite, nakhlite, chassignite and ALH 84001). NWA 7034 was classified as an ungrouped planetary achondrite until the Meteoritical Society approved the new designation "Martian (basaltic breccia)" 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.