rock layers on Mars

Mars was probably flooded billions of years ago

Contributed by
Nov 6, 2018, 1:56 PM EST

Humans have been hypothesizing about water on Mars since before rovers, landers, and even NASA existed. Now scientists have unearthed something about the Red Planet that could mean it had more H2O than we previously thought.

Martian rocks have revealed the Red Planet could have been flooded in areas before getting radiation-bombed into the dusty expanse it is today. While there is evidence for water ice at the Martian poles and hydrated salts, or molecules of water are attached to grains of salt, what NASA’s Curiosity Rover found could mean depths of up to 65 feet. Sedimentary rocks discovered by Curiosity in Gale Crater may be proof of water on Mars like you'd never imagine.

The Noachian period was a tumultuous era on Mars. Around 3.7 to 4.1 billion years ago, the planet was being repeatedly head-butted by meteorites and asteroids (which formed many of its gaping impact bases), but is also thought to have been flowing with liquid water.

“Flood waters entered Gale crater through its southwestern rim and flowed northward,” said Jackson State University researcher Ezat Heydari and colleagues in a recent study that examined asymmetrical ridges in Gale Crater that they say are “indicative of deposition by large floods rather than sedimentation by ordinary fluvial systems.”

NASA Curiosity Rover on Mars

Curiosity on Mars. Credit: NASA

Meaning, these are no ordinary rivers—even ordinary extraterrestrial rivers.

Heydari’s research team used images of rocks that have been taken by Curiosity since it touched down on Mars in August of 2012. The rover has traversed some 65 feet of Gale Crater and explored about 400 meters of sedimentary rock that formed from four different gravel deposits over time. The Hummocky Plain Unit is the most noteworthy of these deposits. The images of this area the Curiosity beamed back to Earth showed asymmetrical ridges, whose rounded lumps and cross beds, or groups of layers on an incline, indicated that they probably wouldn’t have ended up where they did without water to carry them.

The asymmetry of these ridges further supports Heydari’s conviction that Gale Crater was flooded billions of years ago. "These ridges are asymmetric," he told "In other words, they were formed by one directional current."

There is also a parallel to flood deposits on Earth. The crater’s immense gravel dunes mirror huge ripples found in Lake Missoula and the Altai mountains, which were formed from deposits during the Pleistocene Epoch. The ripples on our planet happened during glacial outbursts that happened when glacial lakes finally gushed past the hulking masses of ice holding them back.

“This suggests that Martian floods originated by glacial outbursts, as did their Earth’s counterparts,” Heydari and colleagues concluded.

Does all this water mean ancient aliens? That remains unknown, but Mars 2020 might just find out.


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