The mystery of Mars’s icy spiral canyons revealed

An investigation led by researchers from the Planetary Science Institute (PSI), in collaboration with other universities in Pardue and Arizona (also in the USA) and the Autonomous University of Barcelona, ​​explains the origin of the spiral cannons dug in the ice of pNorth of Mars. The study is published in the journal Scientific Reports.

These canyons had already been studied by numerous scientists who related their distribution to sublimation processes, by which the ice would go directly from the solid to a gaseous state, but their origin and characteristic spiral shape has been a mystery for decades.

These spiral ice canyons on the north pole of Mars have been eroded in situ, with an excavated volume 10 times that of the Grand Canyon of the Colorado, making them one of the largest and youngest geological megastructures in the solar system.

Now, according to the authors of the new work, these gigantic ice depressions have been eroded in situ, with a total volume excavated 10 times greater than that of the Grand Canyon of the Colorado, which makes them one of the largest and youngest geological megastructures in the solar system.

“The emergence of the spiral pattern was due to intersections of the canyons, as they grew, on the dome-shaped geometry of the polar cap,” he points out. Jose Alexis Palmero Rodriguez, PSI researcher who led the study.

This enormous amount of excavated ice would have been carried by the winds and deposited in the form of mantles at mid-latitudes, and even preserved in mountain glaciers at lower latitudes.

Katabatic winds

“Our research suggests that the canyons were formed by loss of ice due to the action of katabatic winds, those that descend from high altitudes, and that exposed ancient ice on the polar surface,” explains the co-author. Ali M. Bramson, a researcher at Purdue University.

Digital elevation model of the north polar cap of Mars showing the spiral canyon system. The red dots indicate the position of 424 hills and depressions in which a sequence of concentric layers is evident, showing that in situ erosion was generalized. For comparing sizes, the Balearic Islands are shown. Right, detail of an eastern sector of the canyon system (top) with a size equivalent to that of the Colorado Canyon (bottom). / MOLA Science Team, MSS, JPL, NASA / Google Earth

“The cannons were formed between a few million years and 50,000 years, during periods of time in which Mars has been continuously in freezing conditions. Therefore, this ice would have been formed by reverse sublimation, without becoming liquid “, he explains Mario Zarroca, researcher at the Department of Geology of the Autonomous University of Barcelona and co-author of the study.

The ice in these canyons would have been formed by sublimation, without becoming liquid, so it would not be a candidate to harbor signs of life, but it could be a water resource for future manned missions

“This makes this ice not a candidate for harboring possible signs of life,” he adds. But for the same reason it can be considered as a possible “pure” water resource, available for future colonization missions to Mars. Taking into account that an ice mass equivalent to twice the volume of the Baltic Sea is estimated, the availability of this resource could be guaranteed for a long time on the planet ”.

Zarroca highlights another of the main implications of this research: “These canyons have been able to expose a paleo-climatic record that it could cover a few hundred million years, and that it could help to better understand the great changes that the conditions of Mars have undergone throughout its history, such as the evolution of its atmosphere and hydrosphere ”.

Ice from the time of the dinosaurs

For comparison, the oldest ice records on Earth do not exceed 3 million years. “Having a record of a few hundred million years, here, would have allowed us to investigate the ice from the time when dinosaurs still populated the Earth, which could help to solve the unknowns surrounding the mega-extinction that took place ago about 66 million years, ”says Palmero.

A record as extensive as that which would have been exposed in the polar ice cap of Mars offers a great opportunity to advance in the knowledge of the evolution of this planet, which has great similarities with our own, the researchers conclude.

Reference:

Rodríguez, JAP, Tanaka, KT, Bramson, AM, Leonard, GJ, Baker, VR, Zarroca, M. “North polar through formation due to in ‑ situ erosion as a source of young ice in mid ‑ latitudinal mantles on Mars”. Scientific Reports, 2021

Rights: Creative Commons.