Perseverance finds key rocks to find out if there was life on Mars

Perseverance’s work on Mars it’s already bearing fruit and select samples to send back to Earth. Rocks that appear to have been weathered by water and are good candidates for harboring organic matter that may indicate if there was life in the past.

The latest discoveries of the robot of the Nasa described in four articles published today by Science and Science Advances, in which the Spaniards Juan Manuel Madariaga, from the University of the Basque Country (UPV/EHU), and Alberto González Fairén, from the Center for Astrobiology (CAB).

The new studies collect the first 250 days of the rover’s mission, during which it gave “very important results”, such as find igneous (magmatic) rocks and with aqueous alterations at the base of the Jezero crater, says Madariaga, signatory of two of the surveys, to Efe.

these rocks May be the key to finding signs of past life on Mars and to date the history of magmas at this location.

Since February 2021, Perseverance has been studying the Jezero crater, north of the Martian equator and formed by the impact of a superbolide. The presence of rivers crossing the crater wall They would have transformed it into a lake, according to scientists, and some time later, not yet specified, elements of volcanism were recorded.

One of the investigations in which Madariaga worked studied the weathering of rocks by water. In them “we found, by surprise”, salts whose presence in igneous environments can only be found because “at some time they have been in contact with water, they cannot be produced from no other way”.

The scientist indicates that “at present, this type of rock and what it contains inside are very good candidates for harbor organic matter that could be an indicator that there was life”but these are analyzes that Perseverance cannot do.

During its journey, the robot selects samples to send to Earth as part of a NASA and European Space Agency (ESA) mission, which it would arrive here in 2033 to be analyzed in the laboratory and obtain answers.

Findings from the rover, which now sits at the base of the crater about two kilometers from the old delta, could also provide evidence to establish a chronology of its geological history and the researchers saw things they didn’t expect.

In its composition, the base of Jezero is different from what has been found in other adjacent areas and “it’s one of the big questions that needs to be answered, what happened to have these differences”.

The first “great unexpected phenomenon” is that there was no found sedimentary rocksagainst “the great starting hypothesis” because it was a lake, on the contrary, what was found are igneous rocks, says Madariaga.

The team believes that the lack of sedimentary rocks reacts to strong wind erosion combined with the necessary chemical weathering.

Thanks to the Meda instrument, an environmental dynamics analyzer aboard Perseverance and run by the Spanish Center for Astrobiology, it was found that there are much stronger winds there than in other places and whirlpools, “we did not know them before our arrival”.

The signs of erosion of these igneous rocks indicate that they have been “exposed to external environments for a very long time” and age can only be determined when examined on Earthbut we know that they are posterior to the formation of the crater, about 2,000 million years.

The researchers consider two hypotheses on the origin of these rocks, which would be the result of volcanic events in the crater or that they were generated by external lava flows that entered them. Likewise, we will have to wait for laboratory tests to have more data.

Volcanic rocks, Madariaga explains, have essentially three mineral components: olivines, pyroxenes and feldspars. The different relationship between them and the chemical nature of each depends on the characteristics of the initial magma.

In the rocks analyzed, those that come from the highest part of the base of the crater have an almost negligible amount of olivine and could have formed underground and cooled slowly, unlike those found below.

Perseverance has Spanish participation, which focuses particularly on Meda and Supercam instruments. The latter can examine Martian rocks and minerals with various techniques define its geochemical and mineralogical characteristics.

Madariaga points out that these instruments “show that they are essential, because they gave results conditioned by what we now know and the new hypotheses that we formulate”.

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