A new paper published in the journal Icarus and led by Cathy Weitz provides evidence for a long history of flowing water in a region of Mars known as Ladon basin. The basin contains deposits of clay-bearing sediments. Weitz notes: The presence of clays indicates an environment favorable for life because clays form and remain stable under neutral pH conditions where water persists long-term that minimizes evaporation to form other minerals like sulfates.

Using several instruments and imagers onboard the Mars Reconnaissance Orbiter, Weitz and her team identified the clay-bearing deposits. These clays initially formed up in the nearby highland terrains and collected at the bottom of a lake in the basin, just as sediment does here on Earth. The basin surface is relatively flat, meaning the lake persisted for a long period of time. Additionally, Weitz explains: We found that the Ladon basin region… records a long history of flowing water beginning relatively early in Mars history around 3.8 billion years ago that continued until up to 2.5 billion years ago, which is considered relatively recent.

A nice low-energy lake sitting around for about a billion years? Sounds like a great place to search for signs of past life.

More Information

PSI press release

“Clay sediments derived from fluvial activity in and around Ladon basin, Mars,” Catherine M. Weitz et al., 2022 June 3, Icarus