Signs in Martian Soil Point to Habitable Conditions For Life Over a Long Period

Is there life on Mars? Has there ever been? It's one of the most important unanswered issues we have about our neighboring planet, but recent study suggests that there may be one region of the red planet that has supported life on several occasions over the course of billions of years.

Planetary scientists have discovered clay-bearing sediments in the northern Ladon Valles, the southern Ladon basin, and the southwestern highlands surrounding the Ladon basin - all parts of the heavily cratered Margaritifer Terra region. This discovery was made after a thorough analysis of images taken by the Mars Reconnaissance Orbiter.

Given that clay forms in an environment with a neutral pH and little water evaporation, it suggests the long-term presence of water. From around 3.8 billion years ago to approximately 2.5 billion years ago, according to the research team, water was present here.

"In addition, colorful light-toned layered sediments that display relatively low bedding dips and contain clays across 200 kilometers [124 miles] in distance are evidence that a lake was most likely present within Ladon basin and northern Ladon Valles," explains senior scientist Catherine Weitz of the Planetary Science Institute in Arizona.

"The low-energy lake setting and presence of clays support an environment that would have been favorable to life at that time."

While it's not quite proof of life — to really establish that, we'd need to dig up fossils on Mars — it does point to possible circumstances that may have supported life. The most recent study attempts to deduce conditions on Mars from what we can observe of its surface and deposits.

Clays, according to the experts, are believed to have first developed on higher terrain above the Ladon basin before being eroded by water channels and carried downstream into a lake in the Ladon basin and the northern Ladon Valles.

The scientists determined that the southwest Ladon basin would have had the most recent water flow. The deposits here correspond to the Eberswalde delta, a region of Mars that is located just south of the study area.

"Our results indicate that the clay sediments deposited by running water in Eberswalde were not unusual during this more recent time because we see many examples of similar young valleys that deposited clays in the region," according to Weitz.

Though liquid water is being sought for, we are aware that Mars has ice. This most recent study supports the notion that flowing water originally covered a significant portion of the Martian terrain and may have brought life with it.

Determining whether or not life might have supported at some point depends on how transitory or otherwise water has been on Mars. Clays and other rocks that the researchers discovered are distributed in a way that is compatible with water remaining in the area.

Clays are additionally nutritional providers and environmental stabilizers. It is far more likely that organisms will be able to live if they have access to water, nutrients, and stable environments.

"Habitable conditions may have occurred repeatedly in the region, at least periodically, until relatively late in Mars history," the researchers state in their published report.

The research has been published in Icarus.