ESA has published images of the area of the planet Mars known as Libya Montes taken by its Mars Express space probe. It’s a mountain range near the Martian equator and is one of the oldest in Mars, altered by volcanic processes and impacts but also by processes associated with the existence of rivers. In the pictures it’s possible to identify various channels and valleys, traces of the ancient water streams.
These discoveries are far from surprising since many scientists have been reconstructing traces of ancient seas, lakes and rivers on Mars using data collected by ESA and NASA space probes and in recent years by the Indian MOM probe. In the area of Libya Montes there are traces of a river, which in the top image goes from left to right, which is actually from south to north, dating to about 3.6 billion years ago. Apparently its origin is in the crater on the left side, after leaving it its course led to the right side.
The geological traces suggest that the water came from the rains of that ancient age, which could be abundant. Rainwater descended from the highest regions to the river and another of that type is visible in the lower right part of the image above. Various activities that formed Libya Montes could be linked to those that formed the impact basin of Isidis Planitia, which with its 1,225 kilometers in diameter dominates the region north of Libya Montes.
Impacts were common at the time and smaller craters are still visible in Libya Montes. The two craters near the center of the image above are even partially superimposed, suggesting a meteorite rain or a large meteorite that broke in Mars’ atmosphere, which was then much denser than the present one. The various craters show different states of erosion and therefore other traces of what happened in that distant time.
The minerals’ examination is important because it shows where there were streams of water. For example, thanks to spectrometric surveys various clay minerals have been discovered that may have been formed only in the presence of water. In Libya Montes, the researchers have reconstructed their formation following the volcanic activity that produced rocks subsequently altered by water and heat. There were hydrothermal sources that probably remained active for tens of thousands of years.
The presence of ancient rivers and volcanoes on Mars is by no means an extraordinary news but finding areas where there could be conditions favorable to life are important. From this point of view, hydrothermal sources are probably the most interesting element because they’re considered potential “cradles” for the birth of life forms. This doesn’t mean at all that they really emerged but these are areas to be further studied.