The fragments of igneous rocks contained in the first sample collected by NASA's Perseverance rover and destined to be brought to Earth within ten years thanks to the future mission will be able to reveal much of the geological history of Mars and the time in which water flowed there. Mars Return Sample, organized with the European Space Agency (ESA).
This is indicated by the results of two studies published in Science and those of two other works published simultaneously in Science Advances.
The sample was collected at the bottom of the Jezero crater, once occupied by a large river delta that flowed into an ancient lake.
"The objective of the exploration of the delta and the Jezero crater is to verify whether in these once habitable environments there are rocks that may contain traces of past life," explains astrobiologist Amy Williams of the University of Florida.
During the collection of the sample, the researchers found that the crater floor is more eroded than expected: the sedimentary rocks expected to be found have been swept away and have given way to the igneous rocks below.
Not bad, because these rocks are the most suitable for establishing the exact age of the delta;
in addition, the fact that they show traces of alteration due to water,
The igneous rocks have a composition similar to that found in some Martian meteorites: they are made up mostly of olivine grains and this indicates that they would have been formed by the slow cooling of a thick layer of magma.
A radar scan made by the Perseverance rover in the first 3 kilometers of its journey into the crater also revealed the stratigraphic and electromagnetic properties of its bedrock down to a depth of 15 meters: its layered structure could be the result of magmatic activity and of repeated exposure to the action of liquid water.