Although Mars currently appears arid, recent findings suggest a different past. Climate likely shifted seasonally, potentially fostering life's emergence.
In the study, titled "Sustained Wet-Dry Cycling on Early Mars" published in the journal Nature, researchers reported that the hexagonal patterns in Gale Crater reflect cyclic wet-dry periods that led to mineral formations fossilized as rock.
In this handout image provided by NASA/JPL-Caltech/MSSS, This color thumbnail image was obtained by NASA's Curiosity rover during its descent to the surface of Mars on Aug. 5 PDT (Aug. 6 EDT) and transmitted to Spaceflight Operations Facility for NASA's Mars Science Laboratory Curiosity rover at Jet Propulsion Laboratory (JPL) in Pasadena, California.
Salt Deposits Found in the Fossilized Hexagonal Patterns
Mars presents well-preserved landscapes with ancient rivers and lakes, contrasting Earth's dynamic tectonic plates that reshape its surface. Despite its harshness, Mars might have held liquid water and a thick atmosphere conducive to life. However, the planet's atmosphere eroded over time, resulting in today's cold and barren conditions.
The Independent reports that a collaboration of researchers from The French National Centre for Scientific Research (CNRS), Paul Sabatier University, and Claude Bernard University Lyon 1, analyzed data from NASA's Curiosity rover, launched in the Gale Crater in 2012.
A few years later, in 2018, Curiosity's discovery of organic molecules hinted at potential past microbial presence on Mars, offering an exciting avenue for exploration.
According to the news release, they used Curiosity's Mastcam1 and ChemCam2 tools and identified salt deposits forming hexagons in 3.8 to 3.6 billion-year-old sedimentary layers.
Resembling terrestrial drying basins, these hexagons mark fossil evidence of Martian seasons. Laboratory experiments suggest such environments promote complex precursor compounds, ideal for life's formation like RNA.
These findings encourage the reevaluation of large-scale orbital images, revealing analogous terrains. Mars' processes that supported life's emergence can now be pinpointed, a phenomenon lost on Earth.
READ ALSO: What Was Mars Like in the Past? Scientists Say Red Planet Was More Beautiful Than Earth Before
Wet Mud Drying Formed the Mysterious Hexagonal Patterns
Unraveling the cyclic climate of Mars before it turned into what it is now has proven challenging, but a team led by Rapin unveils insights into this enigmatic past. The focus of their study is the Gale Crater where NASA's Curiosity rover identified well-preserved hexagonal patterns in sedimentary rock, enriched with calcium and magnesium salts.
These patterns echo those created by mud drying in terrestrial basins, providing clues to Mars' former climate, Science Alert reported. Rather than a single drying event, their research suggests the repeated wetting and drying of mud, with initial T-shaped cracks evolving into Y-shaped intersections over time, culminating in hexagonal formations.
Researchers explained that the concentrated salts within these rocks imply deposition through saline water infiltration, subsequent evaporation, and salt residue.
The rock's thickness indicates prolonged wet-dry cycles persisted, potentially lasting thousands to even millions of years. While Martian microbial life remains unproven, these cyclic conditions were conducive to organizing organic molecules into complex compounds.
Recognizing the widespread presence of organic molecules on Mars, coupled with evidence of these climate cycles, contributes another piece to the puzzle of Martian habitability. The researchers affirm that the undeniable evidence of consecutive wet-dry cycles strengthens the notion that the circumstances in ancient Gale Crater provided a conducive environment for prebiotic polymerization processes.
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