Mars shifts caused by underground salts and melting ice?

A team of researchers led by SETI Institute Senior Research Scientist Janice Bishop, a member of the SETI Institute NASA Astrobiology Institute (NAI), has come up with a theory on the cause of landslides on the surface of Mars.

Previous ideas have suggested that liquid waste stream or dry grain flow causes this movement. None of the models can fully account for the seasonal flow of the Mars area, known as the Recurring Slope Lineae (RSL). The team alternatively assumes that ice melting in the nearby surface causes changes to the surface that make it vulnerable to dust storms and wind. As a result, the RSL functions appear and expand on the surface of Mars today. Furthermore, the team believes that the thin layers of melting ice are the result of interactions between groundwater ice, chlorine salts and sulfates, causing an unstable, liquid flowing slush that causes sinkholes, collapse of the soil, flow of the surface and revolution.

“I’m excited about the prospect of micro – scale liquid water on Mars in environments with a surface where ice and salt occur,” Bishop said. “It could revolutionize our perspective on habitability just below the surface of today on Mars.”

Data on high resolution imaging scientific experiments (HiRISE) from the Mars Reconnaissance Orbiter (MRO) show that RSL lies on slopes against the sun where it continues to appear and / or expand over time. Previous studies have suggested that RSL is associated with chlorine salts and have noted that it occurs in areas with high sulfate. The present study expands these observations with a near-surface crystal activity model based on field observations and laboratory experiments. Mars analog field surveys on Earth, such as in the arid valleys of Antarctica, the Dead Sea in Israel and Salar de Pajonales in the Atacama Desert, show that when salts interact underground with gypsum or water, they cause surface disturbances, including collapse and landslides.

“During my fieldwork at Salar de Pajonales, a dry salt bed in northern Chile, I observed numerous examples of the action of salts on local geology. It is gratifying to find that it may also play a role in formation. of Mars, “he said. Nancy Hinman, professor of geosciences at the University of Montana and member of the SETI Institute NAI team.

To test their theory, the team conducted laboratory experiments to determine what would happen if they thawed Mars’ analogue samples consisting of chlorine salts and sulfates and found them at low temperatures as on Mars. The result was a soft ice formation near -50 ° C, followed by the gradual melting of the ice from -40 to -20 ° C.

“The investigation of the low-temperature behavior of Mars analog permafrost in the laboratory with infrared spectroscopy revealed that thin layers of liquid-like water formed along grain surfaces while the saline soils thawed under Mars, such as the temperature,” Merve Ye said. Ilba said. ?, NASA Postdoctoral (NPP) Fellow at the SETI Institute and Collaborator on the NAI Team.

The modeling of the behavior of chlorine salts and sulfates, including gypsum, under low temperatures, shows how interrelated these salts are. It could be that this liquid water migrates microscale underground on Mars and transfers water molecules between the sulfates and chlorides, almost like sending a soccer ball through the field. Additional laboratory experiments tested these sulfate chloride reactions in a Mars analogous soil with color indicators that revealed the hydration of the salts under the soil and the migration of salt through the soil grains.

“I was delighted to observe such rapid reactions of water with sulphate and chlorine salts in our laboratory experiments and the consequent collapse and upheaval of the small-scale analogue of Mars, which has geological collapse and upheaval functions in karst systems, salt reservoirs and building reservoirs. “collapses on a large scale,” Bishop said.

This project originated from the work on sediments from the McMurdo Dry Valleys in Antarctica, one of the coldest and driest regions of our planet. Just like on Mars, the surface of the dry valleys is acidified regolide by dry winds. However, subterranean permafrost contains water ice, and chemical changes appear to occur below the surface.

“Sediments in the dry valleys provide an excellent test bed for processes that can occur on Mars,” said Zachary Burton, a recent graduate of Stanford University and a contributor to the SETI Institute NAI team. “The presence of elevated concentrations of sulfates and chlorides a few inches below the hard surface landscape in Wright Valley offers an interesting possibility that these water-related mineral compounds and associated processes may also exist on Mars.”

Water ice has been detected below the surface on Mars in soil created on the Phoenix landing site, as well as from orbit using radar measurements and neutron and gamma ray spectroscopy. More recently, HiRISE recorded a view of this ice on the middle latitude. Warmer temperatures (eg -50 to -20 ° C) at equatorial sites on Mars can support liquid water / brine underground during the spring and summer months. RSL observed at some of these equatorial sites is often interpreted as related to larger features called grinds, which are similar to gorges on earth.

“Side branch hole systems on the northern (northward) and northeastern slopes of Krupac crater and RSL at the bottom of the crater wall in this region can, according to our model, be associated with surface features produced by brine activity near the surface.” Virginia Gulick, Senior Research Scientist at SETI Institute and Member of the SETI Institute NAI Team.

In addition to explaining the geological and chemical processes of Mars, this theory also suggests that the martial environment is still dynamic – that the planet is still evolving and active – which has implications for both astrobiology and the future exploration of the Red Planet by the human. The potential for thin water films below the surface on Mars in salty permafrost areas opens new doors to explore habitability.

The paper is published in Scientific progress.