New data from the NASA mission to Mars reaffirms that a crater could be habitable

Thursday, November 24, 2022 | 11:00 p.m.

New data from NASA’s Perseverance rover mission on Mars corroborate that Jezero crater had habitable conditions more than 3,000 million years ago, as orbital images already pointed out.

Three of its instruments confirm that it had liquid water and carbonates in a sedimentary geological environment rich in organic compounds, the Sync news agency reported.

Jezero Crater on Mars was selected as the landing site for the Perseverance rover because images from orbiters such as NASA’s Mars Global Surveyor and Mars Reconnaissance Orbiter, or from ESA’s Mars Express mission, suggested that it harbored a lake long ago. billions of years.

Three articles were published this week in the scientific journals Science and Science Advances in which new results collected by Perseverance in this Martian crater are offered, and all point to the possibility that it was habitable in the past.

Data was collected with three instruments: the Mastcam-Z camera system and the PIXL and Sherloc spectrometers.

One of the authors of the three papers, Alberto González Fairén, a researcher at the Center for Astrobiology (CSIC-INTA) and Cornell University in New York, explained that the in situ analysis of the rover at Jezero revealed “a large number of details that were not visible from orbiters.

Long distance images confirmed that Jezero is a type of delta where the river and lake water have the same density.

Igneous rocks in the crater and sedimentary rocks in the delta

“Second, the PIXL data indicate that the rocks at the bottom of the crater are igneous (they originate when magma cools and solidifies, like volcanic rocks) and that they formed before a river, lake, and delta existed there.” , pointed out González Fairén.

Therefore, combining data they identified “two types of materials in Jezero: igneous rocks in the bottom of the crater, and sedimentary deposits in the delta”.

The cameras of the Mastcam-Z instrument also confirmed that the igneous rocks at the bottom of the crater were formed through two different processes: a part deep underground from magma that slowly cooled, forming characteristic olivine crystals (semi-precious stone ); and the other, from volcanic activity on the surface.

“The large olivine crystals exhibit fractured textures, and the data suggests that they were exposed to at least two different periods of interaction with water,” explained the astrobiologist.

And he clarified: “At first, the interaction was with the carbonated water that circulated filling the lake, which dissolved the olivine and precipitated in the form of carbonates. Much later, distinct periods of interaction (at least two) with small brines left patches of concentrated salts as the fluids evaporated, and this aqueous alteration led to the production of amorphous silicates, sulfates, and chlorine salts.”

Meanwhile, the Sherloc instrument made it possible to identify aromatic organic compounds in the Jezero rocks from two different ancient aqueous environments.

Finally, the spectroscopic analyzes allowed us to identify the presence of aromatic organic compounds in the rocks of the Jezero crater.

Their distribution is spatially correlated with that of secondary minerals, and they appear associated with both carbonates and sulfates, suggesting two epochs of organic compound formation: two different ancient aqueous environments.

“Therefore, the Perseverance analyzes now being published support the picture that Jezero formed a habitable enclave more than 3 billion years ago, in which liquid water and carbonate precipitation existed in an organic-rich sedimentary geologic environment. ”, concluded González Fairén.

Samples to analyze on Earth

Now the Perseverance rover is collecting samples of the different types of rocks from this Martian crater to bring back to Earth for analysis.

The collected fragments of igneous rocks will serve to accurately date the age of the Jezero materials and the temporal sequence of its geological events.

For their part, sedimentary samples will help search for potential indicators of biological activity on Mars in the past.

Specifically, to establish the formation processes of the organic compounds that were identified.

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