Sedimentary Rock Deposits Prove That Rivers Once Flowed Through Hellas Basin on Mars

Survival is a very basic instinct buried deep down into the origins of humanity. We have always been on the lookout for a better environment for our generations to come, owing to the popular belief that Earth may become uninhabitable at some point in the decades to come.

The Red Planet is on the scientists’ hit list for a very long time, with several missions undertaken by NASA to figure out how habitable the planet is. One of those missions was sending Mars Reconnaissance Orbiter (shortly known as MRO) to orbit around Mars. The spacecraft began in its mission in 2006, and it was charged with the responsibility of studying the land, as well as the atmosphere of Mars. The spacecraft was equipped with the best technology of its time, allowing it to perform its mission in the best way possible. One of that equipment is the HiRISE camera, which translates to the High-Resolution Imaging Science Experiment.

After years of orbiting the unknown atmospheres, Mars Reconnaissance Orbiter has sent back a few surface images of the planet using its HiRISE camera that shows that a river might have flowed on the planet in that particular area. A recent study, “Sustained fluvial deposition recorded in Mars’ Noachian stratigraphic record”, was published on 5th May 2020, based on the images captured by the spacecraft.

The images revealed a portion of Hellas Basin, which happens to be located on the southern hemisphere of the planet, and is amongst the three largest known impact basins in the universe. However, the deposits shown in the images could not be observed from a close range, the scientists still made good use of them by converting those high-resolution images into 3D topographical maps.

The sedimentary rocks that were shown in the images, reached heights of up to 200 meters (White Cliffs of Dover are around 100 meters tall) and were 1500 meters wide. Sedimentary rocks do not just build up with the flick of a hand, but they build up layer by layer as water flows over them. The numbers that have been estimated regarding the dimensions of the sedimentary deposits, prove that massive rivers flowed across the basin at some time in the Martian history for hundreds and thousands of years.  

The technology fitted in Mars Reconnaissance Orbiter is slightly outdated and there are rovers on the surface of Mars that were sent for exploration in recent years. These rovers are equipped with much better technology to provide more solid research material on this mysterious planet. The recent discoveries have only motivated scientists and paved the way for better discoveries in the times to come. 

Where did the Water Disappear?

Up till now, scientists have brainstormed if there was ever water on the surface of Mars and if life is still feasible on this extraterrestrial planet? But how did the water cease to exist on this planet?

There are several theories regarding this, one them being that at one-point Mars had a magnetic field that protected its atmosphere from the harsh universe beyond. Once the magnetic field disappeared, so did the planet’s atmosphere, and finally, the water.

However, Jon Wade from the University of Oxford decided to further his research in this regard and he went on studying the chemistry of the rocks that formed the Martian surface. In his research, he found out that the rubble present on Mars was composed mostly of iron oxide. Iron oxide has the tendency to absorb about 25% more water than a normal earthly rock can. This started clearing out some confusions regarding the disappearance of the water from the planet.

Afterward, researchers started to believe that if water was absorbed by the rocks and if those rocks are still present on the surface of the planet, then water may also be present on the planet. Jon Wade clarified that once the rocks absorb the water, not only do they disintegrate the water molecule, but over a passage of time, they also sink deeper down into the mantle of the planet. The oxygen from the disintegrated water molecule is retained by the rock, whereas the hydrogen is lost into the atmosphere.

It is possible to initiate life on the Red Planet, but a life, as complicated as humans, will not survive without water. Even if the planet had retained its atmosphere up till now, water was still bound to be absorbed by the rocks, leaving the surface dry, flaky, and prone to dust storms.      

References

Salese, F., McMahon, W.J., Balme, M.R. et al. Sustained fluvial deposition recorded in Mars’ Noachian stratigraphic recordNat Commun 112067 (2020). https://doi.org/10.1038/s41467-020-15622-0

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