Some of the best clues about Mars are lying in Earth’s deserts, and one of them has just been dated. Teghaza 001, a rose-tinted stone weighing a little under 800 grams, was collected in 2022 on a salt flat in northern Mali. New research in the journal Science, out on Thursday, puts its birth more than 4.1 billion years back, which ranks it in the top three by age among some 435 rocks from the Red Planet found so far.
The rock first puzzled Carl Agee, curator at the University of New Mexico’s Institute of Meteoritics. Its oxygen isotopes marked it as Martian, yet its texture and mix of minerals looked nothing like the usual specimens. NASA’s Jet Propulsion Laboratory then found tiny zircon grains inside, natural clocks that allowed lead author Yang Liu to pin down its age. A Caltech team added a dating method that works on single grains, using a chip smaller than a fingernail and leaving the rest of the stone intact.
Even more intriguing is what it hints about ancient water. Altered minerals and an odd oxygen signature suggest fluids once flowed through the rock beneath the surface, and Agee spotted patches rich in manganese oxide, a compound rovers hunt for as a sign of conditions friendly to life. Together they back the idea that young Mars was warmer and wetter, closer to an Earth-like world than the frozen desert seen today.
Unlike the famous “Black Beauty”, which is a jumble of many rock fragments, Teghaza 001 is one clean rock type. Liu said a reviewer called it “a Rosetta Stone for Mars”. Its chemistry resembles the cratered southern highlands mapped from orbit, although nobody will ever know the exact crater it was blasted from.
