Overflowing old lakes carved canyons on Mars, according to a study

More than 200 of these "paleolakes" have exit canyons of several tens to hundreds of kilometers long and several kilometers wide dug by the water from the old lakes.

A study found that the waters overflowing from ancient lakes on Mars created catastrophic floods that quickly dug canyons on the red planet. The findings suggest that catastrophic geological processes may have played a major role in shaping the landscape of Mars and other worlds without plate tectonics, said Tim Goudge, postdoctoral researcher at the University of Texas at Austin in the USA. "These lacerated lakes are quite common and some of them are quite big, some as big as the Caspian Sea," said Goudge, lead author of the study published in the journal Geology.

"So we think that this type of catastrophic overflow flooding and rapid incision of exit canyons was probably very important on the surface of Mars," he said. By studying rock formations from satellite images, scientists know that hundreds of craters on the surface of Mars were once filled with water. More than 200 of these "paleolakes" have exit canyons of several tens to hundreds of kilometers long and several kilometers wide dug by the water from the old lakes.

However, it was not known if the canyons had been progressively dug over millions of years or quickly carved by a single flood. Using high-resolution photos taken by NASA's Mars Reconnaissance Orbiter satellite, researchers examined the topography of the crater's outflows and edges and found a correlation between the size of the outlet and the volume of the crater. Water likely to be released during a large-scale flood. If the output had been progressively reduced over time, the relationship between water volume and the size of the outlet would probably not be maintained, Goudge said.

In total, researchers examined 24 paleolakes and their canyons across the red planet. The Jezero crater, one of the paleolakes analyzed in the study, is a potential landing site for NASA's search mission, looking for signs of past life. The researchers proposed the crater as a landing site based on previous studies that he had retained water for long periods in the past of Mars. While massive floods from Martian craters may seem like a scene in a science fiction novel, a similar process occurs on Earth as glacially barred lakes cross ice barriers. They found that the similarity is more than superficial. As long as gravity is taken into account, floods create similarly shaped outlets, either on Earth or on Mars.

Although the great floods on Mars and the Earth are governed by the same mechanics, they are part of different geological paradigms. On Earth, the slow, steady movement of tectonic plates radically changes the surface of the planet in millions of years. On the other hand, the absence of plate tectonics on Mars means that cataclysmic events, such as floods and asteroid impacts, quickly lead to changes that can lead to almost permanent landscape changes. "The terrestrial landscape does not conserve large lakes for a very long time," said Caleb Fassett, NASA scientist. "But on Mars, these canyons have existed for 3.7 billion years, allowing us to better understand what deep surface water looked like on Mars," said Fassett.