Evidence of Ancient Ocean Could Suggest Life on Mars

By Isabelle Parker

28 images compiles to show the area near where researchers believe an ocean once was (Photo from NASA/JPL-Caltech/MSSS)

A team of scientists led by Penn State assistant professor Benjamin Cardenas has found new evidence of an ancient ocean in Mars' Northern Hemisphere. Maps published of a region known as Aeolis Dorsa strongly suggest a shoreline left by a large ocean.

"What immediately comes to mind as one the most significant points here is that the existence of an ocean of this size means a higher potential for life," Cardenas said in a statement.

This means that at one point the climate would have had to have been warm enough and the atmosphere thick enough to sustain an ocean. This is in contrast to Mars' current frigid environment, where the only water would have to come in the form of ice.

The shoreline found is roughly 3.5 billion years old, and would have covered hundreds of thousands of square miles as well as being around 900 metres deep. It was identified when researchers looked at Mars' sedimentary record, which is the same method used to find past waterways on Earth. The practice is called stratigraphy, and centres around the idea that water transports sediment as it flows.

From looking at this data, scientists found over 4,500 kilometres of fluvial ridges, which are relics of past water channels filled with elevated sediment. This group is the densest group of fluvial ridges on the Red Planet, and is suggestive of eroded river deltas or submarine channel belts that would have made up part of the ocean.

Researchers concluded that Aeolis Dorsa must have once been covered with a dynamic and rapidly changing ocean, which Cardenas describes as "exactly the type of place where ancient Martian life could have evolved."

Topography map of the Aeolis Dorsa region (Photo from NASA/ DiBiase et al./Journal of Geophysical Research/Benjamin Cardenas / Penn State)