Huge Quantities' of Carbon Emissions Could Be Stored in Rock Found in Earth's Mantle


photo: Wikipedia

Straight away let me say that I wouldn’t get my hopes up that this will solve our carbon capture and storage problems, and even if it went a long way to, there are plenty of other problems with obtaining and burning fossil fuels beyond their carbon emissions. Phew... There’s my preface to what’s a pretty cool discovery.

Scientists have discovered that peridotite, a rock normally found in the Earth’s mantle but which sometimes gets pushed up the surface, could be harnessed to absorb carbon emissions from burning fossil fuelsl. Peridotite naturally absorbs high rates of CO2, but this process could be accelerated scientists say. The full study appears in the Proceedings of the National Academy of Sciences, but here’s the gist of it:Peridotite Naturally Absorbs Large Amounts of CO2
The fact that peridotite absorbs CO2 when exposed to air has been known for some time, but researchers from Columbia University’s Lamont-Doherty Earth Observatory say that the discovery that the rock absorbs such high rates of CO2 underground was unknown. They discovered this when doing field work in the desert of Oman, where there are large areas of exposed peridotite. After examining newly exposed areas caused by road construction they calculated that Omani peridotite was naturally absorbing 10,000 to 100,000 tons of carbon annually.

...Natural Process Could Be Sped Up 100,000 Times or More
Science Codex explains how the scientists think the process could be sped up:

...the process of locking up carbon in the rocks could be speeded 100,000 times or more simply by boring down and injecting heated water containing pressurized CO2. Once jump-started in this way, the reaction would naturally generate heat—and that heat would in turn hasten the reaction, fracturing large volumes of rock, exposing it to reaction with still more CO2-rich solution.

Heat generated by the earth itself also would help, since the further down you go, the higher the temperature. (The exposed Omani peridotite extends down some 5 kilometers.) The scientists say that such a chain reaction would need little energy input after it was started.


Omani Peridotite Could Store 4 Billion Tons of CO2 Emissions Annually
Accounting for engineering challenges and other imperfections, they assert that Oman alone could probably absorb some 4 billion tons of atmospheric carbon a year—a substantial part of the 30 billion sent into the atmosphere by humans, mainly through burning of fuels. With large amounts of new solids forming underground, cracking and expansion would generate micro-earthquakes—but not enough to be readily perceptible to humans...

The original article says the Oman’s state-run oil company is interested in developing a pilot project to test this procedure.

via: Science Codex
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Tags: Carbon Emissions | Carbon Sequestration | Global Warming Solutions