We’re familiar with the dry, dusty landscape that Mars looks like today, but there’s plenty of evidence that the planet once had oceans in the past.
Now, scientists have found strong evidence for a vast ocean on the surface of Mars some 3.5 billion years ago, possibly covering hundreds of thousands of square kilometers.
Although planetary scientists have long believed that Mars was a wetter planet than it is today, the scientific community has been debating whether the northern hemisphere of Mars ever had an ocean.
A Penn State team recently constructed a new topographic map based on a trove of satellite imagery, showing definitive evidence of Mars’ coastline some 3.5 billion years ago.
Mapping waterways by looking at sediment deposited over time, the team found more than 6,500 kilometers of river ridges in the Aeolis Dorsa region that are filled with higher sediment than the surrounding landscape.
The researchers further divided the ridges into 20 systems, suggesting they may have formed from deltas or undersea channel belts, which represent remnants of Mars’ ancient coastline.
The team believes that the Aeolis Dorsa area must have been covered by the ocean, and the sea level has risen significantly.
Rocks were deposited along the basin at such a rapid rate that oceanic remnants are visible in the densest ridge areas on the surface of Mars today.
Since Earth’s ancient sedimentary basins contain information about the planet’s evolving climate, the evolution of life, and more, perhaps Aeolis Dorsa is a good place to start for scientists trying to understand the same on Mars.
Related papers have been published in Journal of Geophysical Research: Planets and Nature Geoscience.