Remains of an ancient glacier spotted on Mars

(CNN) The remains of a glacier have been found near the Martian equator, suggesting that some form of water could still exist in an area on the Red Planet where humans might once have landed.

The ice mass is no longer there, but scientists noticed telltale remnants among other mineral deposits near the equatorial region of Mars. The deposits there mostly contain light-colored sulfate salts.

When scientists looked closer, they recognized a glacier’s features, including ridges called moraines — debris deposited or pushed by a moving glacier. The research team also saw rift fields, or deep wedge-shaped openings, that form in glaciers.

The findings were shared Wednesday at the 54th Lunar and Planetary Science Conference in The Woodlands, Texas.

“What we found is not ice, but a salt deposit with the detailed morphological features of a glacier,” said lead study author Dr. Pascal Lee, a senior planetary scientist at the SETI Institute and the Mars Institute, said in a statement.

“What we think happened here is that salt formed on top of a glacier while preserving the shape of the ice below, down to details like crevasses and moraine bands.”

The researchers think the glacier was 6 kilometers long and 4 kilometers wide, with a height difference of 1.3 to 1.7 kilometers.

Volcanic activity creates a protective layer

Scientists have an idea of ​​how the glacier’s imprint formed, based on evidence of volcanic material in the region. When mixtures of volcanic ash, lava and volcanic glass called pumice react with water, a hard, crusty layer of salt can form.

This annotated image shows all the details of where the glacier once existed.

“This region of Mars has a history of volcanic activity. And where some of the volcanic materials came into contact with glacial ice, chemical reactions would have occurred at the boundary between the two to form a hardened layer of sulfate salts,” the study said. . co-author Sourabh Shubham, a geology doctoral student at the University of Maryland, College Park, said in a statement.

“This is the most likely explanation for the hydrated and hydroxylated sulfates we observe in this light-colored deposit.”

Geologically young surface ice near the equator

The volcanic material likely eroded over time, revealing the salty layer that captured an imprint of the glacial ice and its distinctive features, said study co-author John Schutt, a geologist at the Mars Institute and an ice field guide at the Arctic and Antarctica.

Mars has a thin atmosphere, which allows space rocks to regularly collide with the planet’s surface. But the glacier’s fine, detailed features remain largely untouched in the salt deposit, leading researchers to believe it is relatively “young.”

The study authors said they believe the glacier existed during the geological period in the Amazon region of Mars, which began 2.9 billion years ago and is still going on.

A map shows where the glacial remnants were found near the Martian equator.

“We know of glacial activity on Mars in many places, including near the equator in the distant past. And we know of recent glacial activity on Mars, but so far only at higher latitudes,” Lee said. “A relatively young relict glacier at this location tells us that Mars has experienced surface ice in recent times, even near the equator, which is new.”

The researchers do not know if there is still ice left under the deposit.

“Water ice is currently not stable on the Martian surface near the equator at these altitudes,” Lee said. “So it’s not surprising that we don’t detect water ice at the surface. It’s possible that all of the glacier’s water ice has now sublimated away. But there’s also a chance that some of it is still protected at shallow depths under the sulfate salts .”

Potential for shallow ice pockets

During the study, the team also looked at ancient ice islands called salars in Bolivia’s Altiplano salt flats in South America. Blankets of salt have protected ancient glacial ice from melting or evaporating, leading the researchers to believe a similar scenario may have played out on Mars.

Details of the glacier can be seen in this high-resolution image of the feature.

Next, the researchers want to determine whether there is any ice left from the glacier, and if so, how much is present at shallow depths beneath the salt deposits. If this particular salt deposit protects ice, it’s possible there are other ice pockets nearby.

Orbiters orbiting the planet have shown ice deposits on the frigid poles of Mars, but if water in any form exists in the warmer equatorial lower latitudes, it could have implications for our understanding of the red’s history and potential habitability. planet and future exploration by humans.

“The desire to land humans in a location where they could potentially extract water ice from the ground has prompted mission planners to consider locations at higher latitudes,” Lee said. “But the latter environments tend to be colder and more challenging for humans and robots. If there were equatorial locations where ice could be found at shallow depths, we’d have the best of both environments: warmer conditions for human exploration and still access to ice.”

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