Shifts in our climate have caused glaciers to advance and retreat throughout our geological history (known as ice ages and interglacials), and the movement of these glaciers has carved features on the surface, including letter-shaped valleys. Uhanging valleys, and fjords, these features are missing on the surface of Mars, leading scientists to conclude that glaciers on its surface were fixed in the distant past.
According to the website,RTHowever, new research by a team of American and French planetary scientists indicates that Martian glaciers have moved, but more slowly than those on Earth..
The research was conducted by a team of geologists and planetary scientists from the School of Earth and Space Exploration (SESE) at Arizona State University (ASU) and Laboratoire de Planétologie et Géosciences (LPG) at the University of Nantes in France.
The study was led by Anna Grau Gallover, a 2018 exploration fellow from the School of Earth and Space Exploration” FALSE (Currently in LPG)She was a postdoctoral researcher at Arizona State University when it was performed.
The study, titled “Valley Networks and the Dating of Ice Ages on Ancient Mars,” appeared recently in Geophysical Research Letters..
According to the USGS definition, a glacier is “a large and permanent accumulation of crystalline ice, snow, rock, sediment and glacial aggregate, often here liquid water that arises at the surface and moves downward under the influence of its own weight and gravity.” The key word here is about the movements caused by meltwater gathering under the ice sheet and this eroding the terrain as it moves. On Earth, glaciers have regularly advanced and retreated for several eons, leaving rocks and debris in their wake and carving “features” into the surface..
For their study, Grau-Gallover and her colleagues designed a model of how Mars’ gravity affects how fast the ice sheet moves and how water drains beneath it. Faster draining of water can increase the friction between the rock and the ice, leaving channels under the ice that are likely to persist over time..
It means the absence of these valleys in the form of a letter U The ice sheets on Mars moved and eroded the ground beneath at very slow rates compared to what happens on Earth.
However, scientists have found other geological traces that indicate glacial activity on Mars in the past. These include, inter alia, long, narrow, and winding hills made of sand and gravel layers (eskers) And other features that can be the result of the formation of channels under the ice.
To determine whether Mars has experienced glacial activity in the past, Grau and her colleagues modeled the dynamics of two ice sheets on Earth and Mars that have the same thickness and temperature and have the same meltwater availability under them..
They then adapted the physical framework and ice flow dynamics that describe subterranean water drainage in Martian conditions.
From this, they learned how subglacial puncture would develop on Mars, what effects this would have on how quickly glaciers slide across natural terrain, and how much erosion this might cause..
These findings illustrate how glacier ice on Mars can drain meltwater more efficiently than glaciers on Earth. This would largely prevent lubrication at the base of the ice sheets, which would lead to faster slip rates and enhance glacier erosion..
In short, their study showed that landforms on Earth associated with glacial activity did not have time to evolve there on Mars.
In addition to explaining why Mars lacks certain icy features, the work also has implications for the possibility of life on Mars and whether that life could survive the transition to the global cryosphere we see today..
An ice sheet can provide a constant supply of water and protect and stabilize any sub-glacial bodies of water where life could have originated. It also protects from solar and cosmic radiation (in the absence of a magnetic field) and provides insulation against extreme temperature changes.
These findings are part of a growing body of evidence that life has existed on Mars and has survived long enough to leave evidence of its existence behind..
These findings may also bolster speculation that life on Mars followed the progression of this transition and that much of Mars’ surface water retreated below the surface.