Mars' Canals May Have been Carved by Lava--Not Water: New Insight into the History of the Red Planet

The canals that race across Mars' surface may not have been created by water-at least according to a new study. Scientists have announced that massive lava flows could have created the "canali" on Mars' equatorial region, revealing a bit more about the evolution of this planet.

These gorges, when observed from orbit, resemble terrestrial canyons formed by water. This has led researchers to believe that water was responsible for carving the Noctis Labyrinthus and the Valles Marineris, two of the canyons. Another possibility was that tectonic activity created a large rift valley.

Now, new research has shown that neither of these theories is responsible for the gorges. Instead, it's likely that lava carved the canyon.

The scientists intensively examined the structure of these canyons and their outlets into the Area Vallis and the Chryse Planitia, a massive plain on Mars' low northern latitude. More specifically, the researchers examined thousands of high-resolution surface images taken by Mars probes, including the Mars Reconnaissance Orbiter.

"Everything that I have observed on those images were structures of lava flows as we know them on Earth," said Giovanni Leone, one of the researchers, in a news release. "The typical indicators of erosion by water were not visible on any of them. One must therefore ask oneself seriously how Valles Marineris could have been created by water if one can not find any massive and widespread evidence of it."

Leone may just have an explanation. He believes that it's possible that the volcanic region of Tharsis may be to blame. This region could have been a source of lava flows in the past; when the pressure from an eruption subsided, some of the lava tube ceilings could have collapsed and lead to the formation of a chain of circular holes. Wen lava flowed again through the tubes, the ceilings collapsed entirely and could have formed V-shaped troughs. With the flow of lava over time, these troughs could have been carved into deep canyons.

"If we suppose that lava formed the Noctics Labyrinthus and the Valles Marineris, then there has always been much less water on Mars than the research community has believed to date," said Leone in a news release.

The findings are published in the Journal of Volcanology and Geothermal Research.