A recently analyzed Martian meteorite contains a surprising amount of water and provides insight into an important of Mars’ history. The 2.1 billion year old rock also confirms findings of NASA’s Mars rover, Spirit. More information, as well as how this meteorite fits in with our collection of other Martian meteorites, is in my Nature article, Meteorite carries ancient water from Mars.
Gusev Center is where the rover Spirit found evidence of water. The arrow illustrates the possible flow of water in the past. The recently analyzed Martian meteorite confirms Spirit’s tests.
The meteorite, dubbed Northwest Africa (NWA) 7034, contains a concentration of water by weight about ten times higher than in any of the other 100 or so known Martian meteorites — those rare rocks that get ejected from the Martian surface into space when an asteroid hits the planet, and eventually find their way to Earth. It’s also the only known Martian sample on Earth that hails from a critical period, about 2 billion years ago, when Mars is thought to have become colder and drier than it was originally.
Dating from 2.1 billion years ago, NWA 7034 is the second-oldest Martian meteorite, and provides a “missing link” in the planet’s geological record, according to Agee. (The oldest prospective Martian meteorite, ALH 84001, is 4.5 billion years old, whereas all other Martian meteorites are 1.3 billion years old or younger.) Several lines of evidence indicate that parts of Mars were warmer and wetter, and therefore a possible haven for carbon-based life, some 4 billion years ago. The relatively high water content of NWA 7034, which could be as much as 0.6% by weight, suggests that “crustal or surface processes involving water may have lasted” well beyond the 4-billion-year mark, Agee adds.
The full article is available on Nature’s site.