MIT geologists have found that tectonic activity gives rise to smectite, a type of clay that can sequester a surprising amount of organic carbon within its microscopic folds (shown here), over millions of years. Credit: Anthony Priestas, Boston University
Key points:
- An accordion-textured clay mineral on the seafloor, called smectite, has the ability to sequester carbon over millions of years.
- Analyses revealed that smectite was likely produced after several major tectonic events and sequestered enough carbon to cool the Earth and trigger each of the four major ice ages.
- Researchers are looking into the possibilities of harnessing smectites to buffer human’s climate-warming activities and bring down the world’s carbon emissions.
New research, published in Nature Geoscience, reveals that an accordion-textured clay mineral on the seafloor, called smectite, has the ability to sequester carbon over millions of years.
The research team examined whether oceanic crust crushes against a continental plate could produce carbon-trapping minerals in quantities capable of triggering a global ice age. They compiled geologic data into a weathering simulation and plugged each weathered, “end-product” mineral into a simulation of Earth’s carbon cycle. The combination determined the effect of the mineral on carbon dioxide in the atmosphere.
Their analyses revealed that the mineral smectite was likely produced after several major tectonic events over the last 500 million years. By their estimates, smectite could have increased the preservation of organic carbon by less than one-tenth of a percent. While this is small in absolute terms, over millions of years, smectite accumulated and sequestered enough carbon to cool the Earth and trigger each of the four major ice ages.
“We found that you really don’t need much of this material to have a huge effect on the climate,” explained Oliver Jagoutz, professor at MIT.
These findings are the first to show that plate tectonics can trigger ice ages through the production of carbon-trapping smectite.
Now, researchers are looking into the possibilities of harnessing smectites to buffer human’s climate-warming activities and bring down the world’s carbon emissions. For example, the mineral could prevent exposed carbon from escaping as warming temperatures melt regions of permafrost.
“The influence of these unassuming clay minerals has wide-ranging implications for the habitability of planets,” said study author, Joshua Murray of MIT. “There may even be a modern application for these clays in offsetting some of the carbon that humanity has placed into the atmosphere.”