Washington AFP-JIJI
A meteorite from Mars nicknamed "Black Beauty" could hold vital clues to the planet's evolution from the warm and wet place it once was to its current cold and dry state, NASA said Thursday.
Discovered in Morocco's Sahara Desert in 2011, the 320-gram space rock is about the size of a fist and contains 10 times more water than other Martian meteorites.
It could be the first ever to have originated from its surface or crust.
After more than a year of intensive study, a team of U.S. scientists has determined the meteorite formed 2.1 billion years ago in the beginning of the most recent geologic period on Mars, known as the Amazonian, NASA said.
The abundance of water molecules in the meteorite — about 6,000 parts per million, or 10 times more than other known rocks — suggests aquatic activity persisted on the Martian surface when it was formed.
It is generally accepted that Mars had abundant water early in its existence — scientists ponder if life once existed there — but the nature of its evolution to a cold and dry place remains a mystery.
Known technically as NWA (Northwest Africa) 7034, Black Beauty is made of cemented fragments of basalt, a rock that forms from rapidly cooled lava.
"The high water content could mean there was an interaction of the rocks with surface water," coauthor Andrew Steele said.