Scientists May Have Discovered Mars’ Lost Atmosphere

Mars, once rich with a thick atmosphere and abundant water, has transformed over billions of years into the cold, arid desert it is today, devoid of its once substantial atmosphere.

Two geologists from MIT have proposed that the majority of Mars’ lost atmosphere might be concealed within the planet’s clay-rich crust. Their research suggests that Martian clays could contain about 80% of the planet’s original atmosphere.

The study details how approximately 3.5 billion years ago, Mars’ abundant water evaporated and the atmosphere, rich in carbon dioxide, significantly diminished to the mere trace that remains today.

The researchers theorize that the atmosphere got trapped when ancient water flowing through Martian rocks initiated chemical reactions, converting CO2 into methane, which then became trapped in the planet’s clay deposits for billions of years. This process mirrors similar phenomena observed in certain regions on Earth.

To better understand these processes on Mars, the team examined rock-gas interactions found on Earth. Oliver Jagoutz, a professor at MIT’s Department of Earth, Atmospheric and Planetary Sciences and the author of the study, explained that ample atmospheric CO2 could have been converted to methane and then locked away in Martian clays.

Jagoutz highlighted the well-documented nature of this process on Earth and the presence of similar rocks and clays on Mars, prompting the team to connect the dots between these geological features.

Unlike Earth, Mars lacks significant tectonic activity, which affects the formation and stability of clays. Prior research by the team noted that a type of clay called smectites can sequester carbon for billions of years.

Dr. Murray from the team discussed the substantial carbon storage capacity of these smectite clays. By applying what is known about these minerals on Earth, they estimated how much methane could potentially be stored within the clays of Mars, based on the abundance of clay present on the Martian surface.