Mars surface had more influence from past floods than previously thought

Decades of research indicate that, in their youth, Mars had rivers, lakes, seas and perhaps even oceans — being quite different from the dry, cold world it is today. The surface of the Red Planet has a network of valleys that would have been carved out by water currents over thousands of years — and a new study indicates that catastrophic flooding in Martian lakes would have contributed far more to the formation of these canyons than previously thought.

According to data from previous surveys, more than 200 Martian lakes filled with enough water to cause catastrophic flooding, capable of sculpting part of the planet’s canyons and valleys — about 3.5 to 3.7 billion years ago. “The surface of Mars is covered with impact craters that act as perfect basins for storing water, providing numerous opportunities for large lake break floods,” said Timothy Goudge, planetary scientist at the University of Texas and lead author of the paper.

In analyzing the networks of valleys across the Martian surface, Goudge and his colleagues focused on the marks carved during the peak of activity in the planet’s rivers. Specifically, the valleys connected to old basins that had floors with a higher elevation than those of the lake basins, where they connected. This suggests that canyons formed when these lakes overflowed.

So the researchers calculated the volumes these catastrophic floods excavated from the shape and size of the valleys — about 57,000 cubic kilometers of volume. This value represents 24% of the total volume of the Martian valleys and only 3% of the analyzed valleys. Approximately a quarter of the volume of these valleys was carved out quickly on a geological scale—a matter of days, months, or years.

Goudge points out that certainly these floods of lake breakouts were very important to Earth at some points in its history — for example, when the glaciers melted at the end of Pleistocene, about 11,400 years ago. The large volume of water overflowed many lakes and great floods excavated huge canyons in the northwest of the Pacific Ocean.

The new discovery implies an understanding of how the Martian landscape has changed over time. Since the lake’s gorges formed in catastrophic floods are deeper, they would have influenced the longest-living rivers in the region, explained Goudge. “This is just one example of why a catastrophic lake disruption flood really needs to be considered more consistently as we seek to understand the evolution of Martian river valleys,” said the planetary scientist.

Now the researchers plan to build models of catastrophic flooding in a lake on Mars to understand a little more of this dynamic over time. The research was fully published on September 29, in the magazine Nature.

Source: Space.com

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