Erosion can take many forms. Best known is water that wears away the sides of streams or lakes. However, wind can erode just as effectively, especially if it carries dust particles that can otherwise erode solid objects. While this wind-driven process is most commonly observed on Earth, it plays a role in the history of most other rocky bodies that have an atmosphere. Recently, a team leader of scientists from the Planetary Science Institute found evidence of erosion between 50,000 and a few million years ago in the polar ice cap of Mars. By geological standards, that’s the blink of an eye.
No matter how old they are, the patterns the eroding winds create are breathtaking and transform into a fractal pattern when viewed through the eyes of digital mapping software. The area affected by the winds is also absolutely huge, reaching 10 times the total volume of the Grand Canyon.
Google Earth image of part of the Taylor Glacier in East Antarctica. The erosion process on this part of the earth is similar to that on the polar ice caps on Mars.
Credit: USGS / ERA
The spiral patterns are actually troughs in the ice that are formed as a by-product of the erosion processes. These erosion processes actually carve chunks out of the polar ice cap and expose long-buried ice that is otherwise inaccessible. Models of the ice cap suggest that the newly accessible ice could hold some interesting more discoveries if human or robotic researchers can access it.
One possible discovery is to determine whether or not the water stored in the polar ice cap is fresh water. Much of the readily available water on Mars has dissolved dangerous chemicals like perchlorates that make it unsuitable for human consumption. Purifying this water to make it usable would be both energy and time consuming, none of which will be abundant in an early Mars colony.
UT video about the use of in-situ resources on Mars.
Alternatively, models suggest that the ice exposed as part of the polar ice cap’s erosion process has never been kept in liquid form, and therefore may be free of the contaminants that plague other water sources on the red planet. In that case, the polar cap itself could serve as a reservoir for humanity’s water needs when human explorers finally set foot on Mars.
Another discovery is more scientific than practical, but interesting nonetheless. Models also suggest that the new exposed ice is ancient, dating back hundreds of millions of years. On Earth, scientists regularly drill ice cores to collect data on paleoclimate – the planet’s climate that happened before humans started keeping records. Unfortunately, due to the ever-changing climate on Earth, these techniques were only useful a few million years ago.
Image of some polar valleys on Mars. The orange point indicates a hill, while the blue point indicates a depression. The white arrows point to trough walls that connect the features to locations where erosion may have contributed to their formation.
Credit: MOLA Science Team, MSS, JPL, NASA, via a CTS mosaic Credit: NASA / JPL
Alternatively, the ice cores exposed by erosion on Mars could go back hundreds of millions of years since they were not repeatedly melted and reformed during that time as the cores on Earth did. This would be the equivalent of looking back at the climate during the time of the dinosaurs on Earth. It would give an insight into the red planet’s climate that is further behind than almost any tool currently available on Earth.
This additional information is only accessible if we can reach the exposed ice. No missions are currently planned to search these bags of exposed ice. But if the erosion process continues, there may be even newer areas that need exploring when people finally visit.
Learn more:
PSI – Giant spiral troughs on Mars are young and formed by erosion
Scientific Reports – Formation of North Pole valleys due to in situ erosion as a source of young ice in mantles at medium latitude on Mars
UT – How old is the ice at the North Pole of Mars?
UT – This is the best place for explorers to harvest Mars ice
Mission statement:
The image on the left is an image of the northern polar ice cap of Mars with digital enhancement that specifically highlights the eroded trough spirals. The red dots mark hills and depressions. There’s a snippet of Hawaii’s big island for scaling. The image at the top right is a zoom, the size of which corresponds to the Grand Canyon (see bottom right)
Photo credit: MOLA Science Team, MSS, JPL, NASA.
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