(ORDO NEWS) — The weight and slow movement of glaciers have left characteristic valleys and fjords on the surface of the Earth.
Since there are no similar landscapes on Mars, the researchers believed that the ancient ice masses of the Red Planet were firmly frozen to the surface. The new study suggests they weren’t standing still, but were simply moving very slowly.
Movement is part of the life of a glacier. On Earth, meltwater accumulates under glaciers and icy surfaces, making these icy rivers flow smoothly.
A new study has modeled how Mars’ low gravity affects the feedback between rapidly sliding ice sheets and how water flows under the ice. The rapid flow of water would increase the friction of the ice on the rocks.
This means that the ice sheets on Mars likely moved and eroded the ground beneath them extremely slowly, even when water accumulated under the ice. So say the authors of a new study published in Geophysical Research Letters.
“Ice is incredibly non-linear. The feedbacks associated with glacier movement, glacial water runoff and glacial erosion will lead to fundamentally different landscapes on Earth and Mars,” said Anna Grau Galofre, planetary scientist at the Laboratory of Planetology and Geosciences and lead author of the new study.
Although Mars does not have the obvious U-shaped valleys that are typical of Earth’s glacial landscapes, Grau Galofre said, the researchers, however, found other geological signatures that indicate that there were glacier-like ice masses in Mars’ past, including gravel ridges. called eskers, and potential channels under glaciers.
“While on Earth you get drumlins, lines, scours and moraines, on Mars you will typically see channels and esker ridges under the ice sheet with exactly the same characteristics,” said Grau Galofre.
Grau Galofre et al. simulated the dynamics of two equivalent ice sheets on Earth and Mars with the same thickness, temperature, and subglacial water.
They adapted an existing physical framework describing the drainage of water accumulated under Earth’s ice sheets, combined with the dynamics of ice movement, to model conditions on Mars and study whether drainage under glaciers would evolve towards efficient or inefficient drainage configurations, and what effect will have this configuration on the speed of glacial slip and erosion.
“In the transition from early Mars with surface liquid water, extensive ice sheets and volcanism to the global cryosphere that Mars is now, there must have been an interaction between ice masses and basal water at some point,” Grau Galofre said.
“It is hard to believe that in the 4 billion years of Mars’ planetary history, the conditions for the growth of ice sheets with the presence of subglacial water have never been created, since this is a planet with extensive water reserves, large topographical variations, the presence of both liquid and frozen water, volcanism and greater distance from the sun than the earth.
The results of this simulation demonstrate that glacial masses deplete their base meltwater much more efficiently on Mars than on Earth, largely preventing any formation of water at the base of ice sheets that could lead to rapid slip rates and increased glacial erosion.
According to this study, the typical ruled landforms found on Earth would not have had time to develop on Mars.
The work also opens up possibilities for the survival of possible ancient life forms on Mars, the authors say.
An ice sheet can provide a constant supply of water, protection and stability for any subglacial reservoirs such as lakes, shelter from solar radiation in the absence of a magnetic field, and insulation from extreme temperature fluctuations.
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