Floods probably cut Mars ‘stairs’

Sudden tremendous gushes of water from underground most likely carved out unusual fan-shaped geological formations like staircases long ago on the surface of Mars, scientists said.

The Martian surface has about 200 large basins with fanlike formations, about 10 of which are terraced with what look like steps into the basin. Since they were first seen three years ago, scientists have debated how these formations, some of them nine miles wide, were created.

Dutch and U.S. researchers dug a crater in sand in a room-size tub, then started water flowing in through a channel. The water eroded the sediment, then fanned out and deposited sediment as deltas, building steps into the basin.

Erin Kraal, a researcher at Virginia Tech University who led the study published in the journal Nature, said these Martian formations probably formed quickly, in a period of decades -- not thousands or millions of years.