MIT Scientists Trace 80% of Mars's Missing Atmosphere to Smectite Clay

2 articles · Updated · Sky at Night Magazine · Jun 12

MIT researchers say Mars’s missing carbon atmosphere may be locked underground in smectite clay, with a 1,100-meter global layer able to store about 1.7 bar of CO2.
The team linked the loss to water reacting with olivine-rich volcanic crust, producing methane and transforming rock into smectite whose folded structure can trap carbon-bearing molecules for billions of years.
That mechanism helps explain why Mars appears to have lost at least 90% of its carbon despite atmospheric escape accounting for only part of the planet’s drying and thinning air.
The finding complements a 2024 seismic study that placed enough liquid water to cover Mars 1 to 2 kilometers deep at 11.5 to 20 kilometers below the surface.
For future missions, the clay-trapped methane may be more accessible as fuel than the much deeper water, which remains scientifically valuable but difficult to extract.

Sources

Sky at Night Magazine4h ago

MIT Scientists Locate Mars's Missing Atmosphere Trapped in Underground Smectite Clay

Sky at Night Magazine4h ago

Mars's missing water and atmosphere finally tracked down

Mars's lost atmosphere is now fuel trapped in clay. Can we mine it to power our return journey from the Red Planet?

Mars holds a hidden ocean and a trapped atmosphere. Could releasing them resurrect the Red Planet and unveil its past life?

If a hidden Martian ocean harbors pristine life, are we explorers discovering a new world or contaminants destroying one?

Mars’s Lost Atmosphere Wasn’t Lost: MIT Study Finds Most CO2 Trapped in Planet’s Clays

Overview

A groundbreaking study by MIT researchers in 2024 has revealed that up to 80% of Mars's original carbon dioxide-rich atmosphere was not lost to space, but instead became trapped within smectite clays in the planet's crust. This happened as ancient water flowed through Martian rocks, triggering chemical reactions that converted atmospheric CO2 into methane and then locked the carbon into clay minerals. This discovery provides a clear explanation for Mars's missing atmosphere and fundamentally changes our understanding of the planet's geological and atmospheric history.

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