A group of Icelandic and American scientists are experimenting with a different way of storing carbon dioxide underground.

They are planning to dissolve carbon dioxide in water at high pressure and inject it into basalt formations at a depth of 400 to 800 metres.

They expect that the liquid will permeate through pores in the basalt and react with it to form calcite. Mineral calcite is stable for thousands of years.

Basalt is one of the most reactive types of  rock on Earth and this is the same chemical process by which limestone is formed in nature over many thousands of years. The experiment aims at accelerating the natural process.

The research program, called CarbFix, will include a field scale injection of CO2 at Hellisheidi in south-west Iceland, laboratory based experiments and large scale plug-flow experiments.