Lately the news and discoveries about Mars are brought by Perseverance, but we must not forget that there are other vehicles on the red planet. One of them is the InSight, which arrived in 2018 and went into hibernation due to energy problems a few months ago but little by little has managed to recover enough to be able to analyze the Martian subsoil.
A thirsty “sandwich” between two layers of ancient magma
Probe Has got use his seismograph, whose readings suggest that under the sand and rocks of the surface of Mars it hides a layer of rock from ancient magmatic flows. Beneath it there is more sand and sedimentary rocks (about 200 meters and 30-40 meters thick), before returning to a layer of firm rock.
This first layer of magmatic rock is estimated to be 1.7 billion years old, while the bottom layer of that same material may be 3.6 billion years old. At that time Mars (and Earth) were young planets with high volcanic activity.
For Bruce Banerdt, a geophysicist at the California Institute of Technology, the fact that there is a layer of sedimentary rocks between these two layers of old solidified magma may imply that there was a “pause” in volcanic activity on Mars, long enough that a not-exactly layer of sand and rocks could settle.
In the short term, these first InSight results will help us locate better places to land future probes and rovers. In the longer term and when the analyzes are more precise, these rock layers will help us understand the origins of Mars, the possibilities of whether it ever supported life, and extrapolate what we discover to the history of our own planet.