First Meteorite Linked to Martian Crust
The unique meteorite, dubbed Northwest Africa (NWA) 7034, has some similarities to, but is very different from, other martian meteorites known as SNC (for three members of the group: Shergotty, Nakhla, and Chassigny). SNC meteorites currently number 110. And so far they are the only meteoritic samples from Mars that scientists have been able to study. However, their point of origin on the Red Planet is not known. In fact, recent data from lander and orbiter missions suggest that they are a mismatch for the martian crust.
As co-author Andrew Steele, who led the carbon analysis at the Carnegie Institution’s Geophysical Laboratory explained: “The texture of the NWA meteorite is not like any of the SNC meteorites. It is made of cemented fragments of basalt, rock that forms from rapidly cooled lava, dominated with feldspar and pyroxene, most likely from volcanic activity. This composition is common for lunar samples, but not from other martian meteorites. This unusual meteorite’s chemistry suggests it came from the martian crust. It is first link thus far of any meteorite to the crust. Our carbon analysis also showed that the meteorite likely underwent secondary processing at the martian surface, explaining the macromolecular organic carbon.”
“Perhaps most exciting is that the high water content could mean there was an interaction of the rocks with surface water either from volcanic magma, or from fluids from impacting comets during that time,” said Steele. “It is the richest martian meteorite geochemically, and further analyzes are bound to unleash more surprises.”
The research was supported by NASA’s Cosmochemistry Program, a NASA ASTEP and NAI grant to Steele, the New Mexico Space Grant Consortium, and NSF award ATM0960594.