Mars’ ancient, now dried up oceans were older and much more shallow than previously believed, according to new research published in the journal Nature.
The study comes from researchers at the University of California, Berkeley, who connected the existence of Mars’ early oceans to the rise of our solar system’s largest volcanic system, Tharsis. That link is important because it suggests that global warming allowed liquid water to exist on the Red Planet.
In the new study, the team built a model that helps explain how water first came to the Red Planet. They believe the oceans formed 3.7 billion years ago, which puts them right before or at the same time as Tharsis. As the mountains were much smaller back then, they did not disrupt the planet as much as they did later on. That means the seas would have been relatively shallow, holding just half the water previous estimates assumed.
“The assumption was that Tharsis formed quickly and early, rather than gradually, and that the oceans came later,” explained study co-author Michael Manga, a professor at the University of California, Berkeley, according to Phys.org. “We’re saying that the oceans predate and accompany the lava outpourings that made Tharsis.”
The team’s research showed that Tharsis spewed gas into the atmosphere, a process that caused the global warming that created liquid water. The volcanic eruptions also generated channels that allowed underground water to reach the surface and fill the northern plains.
While some people are skeptical that Mars once had oceans, this research gives compelling evidence for the bodies of water. In addition to the research, scientists also found a series of irregular shorelines that suggest the volcano system depressed and deformed the land as it grew. Such a process may have created natural irregularities in rock height, especially if the oceans formed during Tharsis’ early years.
Though more work needs to be done, this research is a good start to understanding Mars’ oceans. The team plans to continue mapping and dating to see what else they can discover about the Red Planet’s past, and they hope NASA’s next Mars lander, InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) will help them in such endeavors.
“It could potentially detect the presence of subsurface frozen water, which could be a remnant of a past ocean,” said lead author Robert Citron, a planetary scientist at the University of California, Berkeley, according to Space.com.