It is known that traces of ancient rivers are found throughout Mars. In satellite data, they appear as long rises called river ridges because sediment in river beds eroded more slowly than the surrounding terrain. However, the Curiosity rover, examining the relief of Gale Crater, discovered landforms in the form of ledges and short truncated ridges (“noses”), which are not traditionally associated with ancient fluvial deposits.

Scientists mapped the erosion of ancient Martian soil by training a computer model on Curiosity satellite images and 3D scans of layers of rock deposited over millions of years beneath the seafloor of the Gulf of Mexico.

The researchers then modeled Martian crater erosion over millennia, adding the effects of wind, which currently causes erosion on Mars. It turned out that in this case, topographic ledges and protrusions are formed inside the craters, and not typical ridges formed by river deposits. Thus, these landforms serve as indicators of ancient fluvial deposits in crater-like river ridges on Mars.