Could signs of Mars life be hidden in its thick layers of clay?
The thick and mineral clay layers found on Mars suggest that the red planet hosted potentially welcoming environments for long stretches in the old past, suggests a new study.
Clays need liquid water to form. These layers are hundreds of feet thick and would have formed about 3.7 billion years ago, in warmer and weetly wet conditions than what is currently prevailing on Mars.
“These areas have a lot of water but not a lot of topographic uprising, so they are very stable,” said the co-author of the Rhianna Moore study, who conducted research as a postdoctoral scholarship holder at the Jackson School of Geosciences at the University of Texas, in a press release.
“If you have stable terrain, you don’t spoil your potentially habitable environments,” added Moore. “Favorable conditions could be maintained for longer periods.”
On our native planet, these deposits are formed under specific landscape conditions and climatic conditions.
“On Earth, the places where we tend to see the thickest clay mineral sequences are in wet environments, and those with minimal physical erosion that can undress on newly created alteration products,” said co-author Tim Goudge, assistant professor in the Department of Earth and the planetary sciences of the Jackson school.
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However, it is not clear how the local and world topography of March, as well as its past climate activity, influenced the surface alteration and the formation of clay layers.
Using the data and images of the NASA Mars recognition orbiter – the second longest spaceship around Mars, after Mars Odyssey 2001 of the agency – Moore, Goudge and their colleagues studied 150 clay deposits, looking at their forms and their locations, and how close they are of other characteristics or rivers.
They found that clays are mainly located in low areas near ancient lakes, but not near the valleys where water flowed once strongly. This mixture of gentle chemical changes and less intense physical erosion has helped clays to remain preserved over time.
“”[Clay mineral-bearing stratigraphies] tend to occur in areas where chemical alteration was favored in relation to physical erosion, further from the activity of the valley network and closer standing bodies, “the team wrote in the new study, which was published in the journal Nature Astronomy on June 16.
The results suggest that intense chemical bad weather on Mars can have disrupted the usual balance between alteration and climate.
On Earth, where tectonic activity constantly exposes a fresh rock to the atmosphere, carbonate minerals as limestone form when rock reacts with water and carbon dioxide (CO2). This process helps to eliminate CO2 from air, store it in a solid form and help regulate the climate over long periods.
On Mars, tectonic activity is nonexistent, leading to a lack of carbonate minerals and the minimum elimination of CO2 of the thin atmosphere of the planet. Consequently, the CO2 released by Martian volcanoes a long time ago has probably stayed in the atmosphere longer, which makes the planet warmer and more humid in the past – the conditions that the team believe may have encouraged the formation of clay.
Researchers also speculate that clay could have absorbed water and trap chemical by-products such as cations, preventing them from spreading and reacting with the surrounding rock to form carbonates that remain trapped and unable to pivot in the surrounding environment.
“”[The clay is] Probably one of the many factors that contributes to this strange lack of predicted carbonates on Mars, “said Moore.
This article was initially published on Space.com.
