Thick Martian clays may have formed in stable ancient lakebeds

Thick Martian clays may have formed in stable ancient lakebeds
by Clarence Oxford
Los Angeles CA (SPX) Jun 23, 2025

New research led by the University of Texas at Austin reveals that thick layers of clay on Mars likely formed in ancient, stable lakebeds, creating environments that could have supported early life. These clay-rich regions, often spanning hundreds of feet, owe their formation to abundant water and minimal geological disruption, according to findings published in Nature Astronomy.

The study examined 150 clay deposits previously identified by NASA's Mars Reconnaissance Orbiter. Lead author Rhianna Moore, formerly a postdoctoral fellow at UT's Jackson School of Geosciences, found that most of these deposits sit in low-lying terrain near ancient lakebeds but away from areas shaped by strong water flow. This suggests a delicate balance between chemical and physical weathering, leading to long-term preservation of the clays.

"These areas have a lot of water but not a lot of topographic uplift, so they're very stable," Moore said. "If you have stable terrain, you're not messing up your potentially habitable environments. Favorable conditions might be able to be sustained for longer periods of time."

The research was part of UT's Center for Planetary Systems Habitability, which explores the origins and viability of life across planetary bodies. Moore now works with NASA on the Artemis mission to the Moon.

The thick Martian clays may also signal a breakdown in the planet's water and carbon cycles. Unlike Earth, which continuously renews reactive rock through tectonic activity, Mars lacks plate tectonics. As a result, volcanic CO2 may have remained in the atmosphere longer, warming the planet and encouraging clay formation without producing carbonate rocks typically expected under such conditions.

"On Earth, the places where we tend to see the thickest clay mineral sequences are in humid environments, and those with minimal physical erosion that can strip away newly created weathering products," said co-author Tim Goudge, assistant professor at the Jackson School. "These results suggest that the latter element is true also on Mars, while there are hints at the former as well."

Instead of carbonates forming from volcanic rock interacting with water and CO2, the ongoing development of clay may have trapped essential chemical elements, preventing their distribution into the broader environment. This sequestration could help explain Mars' puzzling lack of carbonate deposits.

"It's probably one of many factors that's contributing to this weird lack of predicted carbonates on Mars," Moore added.

Research Report:Deep chemical weathering on ancient Mars landscapes driven by erosional and climatic patterns