Scientists widely agree that Mars once had flowing water and a thicker atmosphere, conditions that would have made the planet habitable. But between about 4.2 and 3.7 billion years ago, its rivers, lakes, and global ocean vanished as the solar wind gradually eroded the atmosphere. Exactly how long Mars stayed habitable remains an open question.
Some researchers argue that habitability ended billions of years ago, while newer studies point to much longer stretches of favorable conditions. Among these are recent results from NASA’s Curiosity rover, which has been studying Gale Crater to uncover more details about Mars’ ancient environment.
Martian Dunes Likely Hardened by Groundwater
New research from scientists at New York University Abu Dhabi (NYUAD) suggests that billions of years ago, ancient sand dunes inside the crater slowly transformed into rock through interactions with groundwater.
Published in the Journal of Geophysical Research: Planets, the study points to the possibility that Mars remained habitable far longer than previously assumed.
The work was led by Dimitra Atri, Principal Investigator at NYUAD’s Center for Astrophysics and Space Science (CASS), with contributions from CASS researcher Vignesh Krishnamoorthy. The team also included Research Instrumentation Scientist James Weston, Postdoctoral Associate Marieh B. Al-Handawi of the Smart Materials Lab, and Professor Panče Naumov, affiliated with multiple NYUAD and NYU research centers.
In their study, the researchers focused on dunes within the Stimson Formation (SF), a collection of wind-deposited sand and sedimentary rock inside Gale Crater. Curiosity has documented multiple examples of these “lithified” features—sediments that have hardened into rock—at this site.
Because Gale Crater is now extremely dry, the team concluded that these rock formations most likely developed during the Noachian Period (roughly 4.1–3.7 billion years ago), a time when widespread flooding and flowing rivers are thought to have shaped the region.
Comparing Martian Data with Water-Formed Desert Rocks on Earth
The scientists drew on data from the Mars Science Laboratory’s Curiosity Notebook, which houses information from the rover’s instruments. They compared these observations with rock formations in the deserts of the United Arab Emirates (UAE), where similar structures are known to have formed through interactions with water.
The team concluded that the Stimson Formation resulted from late-stage water activity, likely created when groundwater from a nearby mountain interacted with the dunes.
They also discovered that this process produced minerals like gypsum—a soft calcium sulfate dihydrate (CaSO₄) commonly found in Earth’s desert environments.
This new study aligns with results Krishnamoorthi and Atri presented last year at the Tenth International Conference on Mars, held July 22–25 at Caltech. In that earlier work, they analyzed data from the Greenheugh Pediments (GP), another nearby dune system featuring similarly hardened rock layers.
In both locations, the researchers suggest that interactions between dunes and subsurface water produced these unusual formations—findings that could be highly important for efforts to detect past or even present life on Mars.
Martian Rock Deposits Could Preserve Signs of Ancient Microbial Life
On Earth, sandstone layers preserve some of the oldest traces of life, including microbial communities that stabilize sediments and trigger mineral formation. Using these Earth examples as a guide, Atri and Krishnamoorthi’s team propose that the lithified deposits in Gale Crater may hold fossilized remnants of ancient Martian microbes.
Beyond offering fresh clues about Mars’ transition to the cold, arid world it is today, this research points to promising sites for future missions aimed at continuing the search for life.
Read the original article on: Sciencealert
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