A meteorite discovered in the desert of Morocco is a 4.4-billion-year-old piece of the crust of Mars, and may reveal the character of much of the Red Planet's surface, a new analysis suggests.
It's not red, however; the dark chunk of space rock has been dubbed "Black Beauty" for its dark gray and black hues.
Officially known as NWA 7034 (for NorthWest Africa), it's unlike any other Martian meteorite previously found, say researchers at Brown University in Rhode Island and the University of New Mexico who've conducted new spectroscopic examinations of the rock.
Before Black Beauty, all Martian meteors discovered on Earth have been classified as SNC meteorites -- for shergottites, nakhlites, or chassignites -- mostly igneous rocks consisting of cooled volcanic material.
Black Beauty, in contrast, is breccia, a conglomeration of different types of rock that have been fused together in a basaltic matrix, the researchers report in the journal Icarus.
Sedimentary components in the meteorite chemically match rocks analyzed by NASA rovers on Mars, suggesting it came from the dark crust that underlies the planet's dusty reddish cover.
If so, it may solve a puzzle scientists have been wrestling with; why spectrographic examination of SNC meteorites has never quite matched up with spectral data of the Martian surface gathered from space.
"Most samples from Mars are somewhat similar to spacecraft measurements," says Brown researcher Jack Mustard, "but annoyingly different."
The researchers used an imaging system developed by Massachusetts-based Headwall Photonics to obtain detailed spectral imaging of the entire sample.
"Other techniques give us measurements of a dime-sized spot," says study lead author Kevin Cannon. "What we wanted to do was get an average for the entire sample. That overall measurement was what ended up matching the orbital data."
That matches Black Beauty to the Red Planet's dark plains, areas where the coating of red dust is thin and the rocks beneath are exposed, suggesting the meteorite is a sample of the "bulk background" of rocks thought to be hidden under the red dust on much of Martian surface, Cannon says.
A surface rich in rock like that seen in Black Beauty makes sense given the planet's history, the researchers say in their published study.
"Mars is punctured by over 400,000 impact craters greater than 1 km in diameter," they write. "Because brecciation is a natural consequence of impacts, it is expected that material similar to NWA 7034 has accumulated on Mars over time."
That's what you'd expect on a planetary surface that has been broken apart and then reassembled by constant bombardment and cosmic impacts, they say.
"This is showing that if you went to Mars and picked up a chunk of crust, you'd expect it to be heavily beat up, battered, broken apart and put back together," Cannon says.
