In the next issue of the Proceedings of the National Academy of Sciences, geologist Peter Kelemen and geochemist Juerg Matter describe a naturally occurring process which can be supercharged to grow underground minerals that can permanently store billions of tonnes of carbon dioxide every year.

When carbon dioxide comes in contact with peridotite, the gas is converted into solid minerals such as calcite. Peridotite, is the most common rock in the Earth’s mantle (the layer directly below the crust). It appears on the surface, particularly in Oman, but also in New Guinea, New Caledonia and along the Adriatic coast.

The scientists, who are both at Columbia University’s Lamont-Doherty Earth Observatory in New York, say that mining the rock and bringing it to the surface would be too expensive. But they could kick-start peridotite’s carbon storage process by boring down and injecting it with heated water containing pressurized carbon dioxide. They have a preliminary patent filing for the technique.

The scientists say that, because the major surface deposits of peridotite in Oman are near the major oil and gas producing region, 4 to 5 billion tons a year of  cabon dioxide could be economically captured and stored near Oman using peridotite.