Meteorites that caused tsunamis on Mars



Today Mars is an immense cold and inhospitable desert, but things were not always like that. In fact, the surface of the red planet is full of signs that indicate that large amounts of water flowed over it in the past: satellite photographs show channels of dry rivers in its terrain and robotic probes that have landed on this dead world They have found minerals that only form in the presence of this liquid. It is even believed that the vast plain that covers much of the northern Martian hemisphere, Vastitas Borealis, was able to house an ocean about 4,000 million years ago.

Of course, it is still unknown if the existence of liquid water allowed the development of life on the Martian surface in the past. What we do know is that our red neighbor came to experience the fury of the oceans.

Signs of a catastrophe

Thanks to the orbiters equipped with high-definition cameras (such as the HiRISE of the Mars Reconnaissance Orbiter probe) that have photographed the surface of Mars with an unprecedented level of detail, geological accidents have been captured that are, at least, curious. Take a look at this photograph, for example:

What you see in this image are a large number of rocks with a size similar to that of cars or houses scattered over a striated terrain. This type of geological structure is surprising because, at present, the erosive forces that act on the surface of Mars are very weak and it is not experiencing volcanic activity, so it is difficult to conceive that the planet will have enough energy phenomena such as to move such a large amount of rocks.

In addition, another characteristic that draws attention to this field of rocks is that it is located in a region where there are ample channels that seem to have been formed by the rapid action of water, in addition to raised terrain with edges that look like they have been sawn by intense currents, forming promontories. Therefore, what kind of aquatic phenomenon is energetic enough to produce such changes?

Effectively. As you have deduced from the title of the article, we are facing the effects of a tsunami.

The cause of tsunamis

The main responsible for the formation of tsunamis on our planet is tectonic activity, but it is likely that the surface of Mars was never affected by this phenomenon. Fortunately (or not), there are other ways to generate giant waves.

The relief formed by giant waves that you have seen just now was identified in a 2016 study in an area that had a slope of about 900 meters high and covered about 570,000 square kilometers. After analyzing the images, the authors of the study concluded that the channels and debris fields that had been scattered throughout this region could not be explained through any other phenomenon that could have taken place on Mars at present or the past, such as ice flows, avalanches, glacier movement, flooding or wind action. Therefore, this landscape could only be the work of the strong water currents that a tsunami produces when it recedes, dragging with it the material with which it comes into contact.

In addition, the existence of two different deposits in the region suggested that it was not hit by one, but by two different giant waves separated by a pause that lasted several million years.

The study estimates that waves between 10 and 120 meters high would be needed to cause movements on the Martian surface that have the observed magnitude. Taking all this into account and considering what is the energy necessary to cause a wave of these characteristics, the authors concluded that the tsunami had to be the result of a meteorite impact on the early Martian ocean. In addition, they calculated that the collision must have been violent enough to produce a crater about 30 kilometers in diameter.

Moreover, a study other than 2019 that analyzed another region of the Martian surface, which seems to have suffered the effects of a tsunami, went a little further. In this case, the authors believe they have identified the crater that excavated the meteorite that generated the giant wave: the Lomonosov crater, a 150-kilometer-diameter structure that has the right age (about 3,000 million years) and whose shape indicates that the terrain was underwater at the time of its formation.

That is, Mars looked much more like Earth in the past, both for good and for bad. And, in this case, its surface was not only covered with oceans, but was also punished by giant waves such as those formed on our planet.

DON’T KEEP IT UP:

  • Although it is true that the conditions on the surface of Mars were much more benevolent in the past and that life could have developed over it, that does not necessarily mean that life will appear. In fact, today no evidence of past life on the red planet has been found.
  • The “Allan Hills 84001” meteorite is famous for coming from Mars and possessing microscopic structures that, at the time, were interpreted as the fossil remains of bacteria. Subsequent experiments have shown that these structures can also be formed through geological processes.

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