Mars once flowed with vast floods that burst and spread over its surface, according to scientists.
Those surging waters carved canyons in the red planet’s surface that are still visible to this day, images show.
The new findings help answer a long question about how the deep craters could have formed on Mars and other planets without plate tectonics like on Earth.
It found they are affected by catastrophic geologic processes that could have substantially altered the planet’s surface.
On Mars’ surface, there are a host of lakes that are now dry but once would have held vast amounts of water. Sometimes, they would become so full that they overflowed, bringing catastrophic floods that would have caused the canyons in just a matter of weeks.
That helps answer the puzzle over whether the canyons were formed over a length of time or in a series of dramatic events. The shape of the rock formations suggest it was the latter, said Tim Goudge, lead author on the paper published in the journal Geology this week.
“These breached lakes are fairly common and some of them are quite large, some as large as the Caspian Sea,” said Mr Goudge. “So we think this style of catastrophic overflow flooding and rapid incision of outlet canyons was probably quite important on early Mars’ surface.”
Satellite images show that Mars has hundreds of craters that were once flooded with water. More than 200 of them have what scientists refer to as paleolakes, with outlet canyons that flow into vast channels of water.
Now scientists have established, using Nasa imagery that showed the details of the outlets, that those were formed quickly as vast amounts of water flowed through them.
On Earth, such dramatic changes happen over millions of years as the tectonic plates move. But on Mars they happen far quicker – and then can be preserved for billions of years.
“The landscape on Earth doesn’t preserve large lakes for a very long time,” co-author Caleb Fassett said. “But on Mars ... These canyons have been there for 3.7 billion years, a very long time, and it gives us insight into what the deep time surface water was like on Mars.”