In a study accepted for publication in the American Geophysical Union's Journal of Geophysical Research-Solid Earth, McGrail and colleagues report that ancient lava flows, perhaps 10 million years old in Washington State, sandwich deep basalt rock layers that would keep carbon dioxide thoroughly bottled up. "A simple fact of the physics of lava flows" reliably creates these layers, McGrail says, about 3,000 feet deep. Just like baking bread, bubbles in lava flows become trapped between the cooling outer crust, making the interior of a lava layer permeable.
Most surprising, the stone within those water-filled layers appears to mix with carbon dioxide to form solid rock, the team reports, alleviating worries about the gas leaking away once it is buried. The process starts within a year to three year's time of injecting the carbon dioxide, astonishingly fast by geological standards. "Essentially we are making limestone," McGrail says.
