The origin of Mars' ancient oceans has long been a mystery to scientists. While it has long been known that these oceans were present in the Red Planet's early years, researchers weren't quite sure where they came from, or why they eventually disappeared. But a new study suggests that a volcanic system on the planet might hold some of these answers while hinting that the oceans formed much earlier than once believed.
In a study published Monday in the journal Nature, a team of geophysicists from the University of California, Berkeley theorized that Mars' oceans were allowed to exist by Tharsis, a large volcanic region on the planet that is considered to be the largest such region in the solar system. According to Newsweek, Tharsis is where Olympus Mons, the largest volcano in the solar system, can be found, and with that volcano and others present in the region, the researchers believe that volcanic eruptions might have caused Mars' climate to warm in such a way that oceans were formed, ultimately resulting in the illusion of the Red Planet holding more water than it actually did.
"This is a hypothesis," read a statement from UC Berkeley geophysicist and study co-author Michael Manga.
"Volcanoes may be important in creating the conditions for Mars to be wet."Previously, scientists had theorized that Mars' oceans formed sometime after Tharsis, which is now estimated to be about 3.7 billion-years-old, according to Science Daily. The new research, however, suggests that the oceans were formed before or around the same time as Tharsis, with the volcanic system slowly growing to its present size, instead of forming "quickly and early," as Manga described earlier theories on the region's formation.
Science Daily noted some of the other interesting takeaways from the UC Berkeley study, including the researchers' explanation of Mars' peculiar shorelines, which vary by as much as one kilometer in height, instead of being consistent in height like they are on Earth. Assuming Mars' first ocean, Arabia, had formed about 4 billion years ago and "intermittently" existed during the first one-fifth or so of Tharsis' growth, this process could have resulted in the Arabia shoreline getting distorted like it is today. This too was observed with the shoreline of another ocean called Deuteronilus, though it was assumed to have formed about 3.6 billion years ago, at a point when Tharsis was in the final one-sixth of its growth.
"These shorelines could have been emplaced by a large body of liquid water that existed before and during the emplacement of Tharsis, instead of afterwards," explained UC Berkeley graduate student and study first author Robert Citron.
While the new study did not offer any new insights on what could have happened to Mars' vast oceans, Citron told Seeker that NASA's InSight mission could eventually offer some definitive answers to that question. However, he stressed that it's merely a possibility at this point that the seismometer NASA will use during the mission would find evidence of underground water that might have originated from the Red Planet's ancient oceans.