Mars' 4.1 billion-year-old secret revealed in the Sahara Desert

A 4.1-billion-year-old Martian meteorite designated Teghaza 001, recovered in the Sahara Desert in Mali, has yielded evidence that water existed in the Red Planet's crust during its earliest geological era and that its rocks interacted with it. The find offers a rare window into a period of Martian history poorly represented in the meteorite record, when the planet's surface and subsurface may have been habitable. Analysis of the sample's chemistry points to aqueous alteration at a time when Mars is thought to have been warmer and wetter. Researchers will next compare Teghaza 001 with other ancient Martian meteorites and rover data to pin down the timing and extent of early crustal water.