Lake floods created a quarter of canyon networks on Mars
(Timothy A. Goudge et al. / Nature, 2021)
A quarter of the canyon networks on ancient Mars were created by large floods from large lakes, not river activity or runoff.
This is the conclusion reached by planetary scientists who studied the networks of valleys on Mars, which fell into the field of view of orbiters.
Thanks to the Martian missions, scientists know that in the past, when the climate on the planet was milder, liquid water flowed along the surface of Mars.
The flows created river channels and deltas, and also filled lakes, some of which were the size of small terrestrial seas.
It is believed that the era of the formation of networks of valleys on Mars ended about 3.5-3.7 billion years ago.
At the same time, despite the fact that there are more than two hundred large lake basins on the planet, the idea that many canyons were formed during powerful floods caused by the breakthrough of lakes was practically not considered
Scientists thought that canyons were mainly formed due to surface processes such as precipitation, runoff from subsurface reservoirs, or melting of snow and glaciers.
Now a group of planetary scientists led by Timothy A. Goudge from the University of Texas decided to investigate the role of lake floods in shaping the relief of Mars in the past.
For this purpose, they used observational data from Martian orbiters and global maps of the planet.
Scientists have concluded that lake floods are responsible for at least 24% of the volume of canyons on Mars, despite the fact that the length of such canyons is only 3% of the total length of river valleys on the planet.
This is because the spill canyons are much deeper than other river channels.
The lake outburst floods, according to researchers, played a major role in creating networks of valleys in the early evolution of Mars
Also, they were similar to the terrestrial floods that took place in the northwestern United States and Central Asia at the end of the last ice age, more than 15 thousand years ago.
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