Researchers in the Wadi Lawayni valley in Oman have found that the rocks that make up the region could be useful for geological carbon sequestration, thus reducing the human carbon footprint.
The rocks in the region are rich in magnesium and calcium, making them more chemically reactive and prone to convert the gas into solid minerals, a process called mineral carbonation.
Peter Kelemen, professor at Columbia University and geology researcher, along with his colleagues, believe that the rocks, exposed through plate tectonic movements, are capturing about 100,000 metric tons of CO2 yearly. As it is, it’s not enough to make a difference, but they believe that through some engineering, it can be enhanced and capture up to “a billion tons of CO2 per cubic km of rock per year”. Oman is home to 15,000 cubic km of this rock.
Kelemen’s proposal is to increase the velocity of the reactions by drilling one to three kilometers down, where the temperatures are higher, and introducing seawater enriched with CO2 taken from the air. The water would penetrate the rock’s pore, then reaching another hole that would act as a chimney to bring water, now free of CO2, back to the surface to be used again.
A few years ago, researchers in Iceland were successful in injecting CO2 into a rock that is chemically similar to the mantle, an important precedent for the ongoing investigations in Oman. A team was scheduled to arrive this May to begin testing of injecting and mineralizing CO2 into the mantle rock.
Similar geological conditions can be found in the surface of Alaska, Canada, California, Japan, New Zealand, and more. According to Kelemen’s calculations, the Earth’s capacity to sequester CO2 ranges from 60 trillion to 600 trillion tons of CO2. A report published by the IPCC in 2019 determined that in order to cap global warming at 1.5o C, between 100 billion to a trillion tons of CO2 have to be removed from the atmosphere by 2100. If the project is successful, and an extensive infrastructure is established by 2050, between two billion to 20 billion tons of CO2 could be eliminated yearly.