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.
While planetary scientists are convinced that Mars was once a wetter planet than it is today, the scientific community has long debated whether Mars’ northern hemisphere once had oceans. 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 that they may have formed from deltas or undersea channel belts, which represent remnants of Mars’ ancient coastline.
The team believes that the Aeolis Dorsa region must have been covered by an ocean, and that sea levels rose significantly and rocks were deposited along the basin at an extremely rapid rate to see marine remnants in the densest ridges 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 starting point for scientists trying to understand the same on Mars.
Related papers have been published in Journal of Geophysical Research: Planets and Nature Geoscience.
(Source of the first image: NASA)
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