Carbon-absorbing rocks and the implementation?

Essentially the researchers discovered that certain rock formation off the coast of Oman has substantial carbon absorbing capability, upto billions of tons a year, if the rock-cracking process can be self-sustaining. For comparison, coal plants in the U.S. emit between 1-2 billion tons per year. Since carbon dioxide travels long distance and stays in the air, then carbons can be stored with little leakage - a major problem that confronts typical carbon capture and sequestration (CCS) techniques.

CCS works by transporting emitted carbon dioxide and pumping it into some underground storage locations, such a porous aquifiers. But the high cost of transport and building pipelines makes it uneconomical. Carbon dioxide leaking from those locations is also a major problem.

Instead, this new proposed method uses the carbon-dioxide-absorbing ability of sea water and a convection system that pumps sea water deep into the rock formation in one hole and releases the "decarbonized" water in another hole. The rock formation peridotite has a large amount of olivine, which contains magnesium and oxygen, among others. The olivine reacts with water and leaves behind large amounts of dissolved magnesium and bicarbonate. With bicarbonate, the carbon concentration in the water can be increased by 10 times as well. As the water gets deeper into the ground and temperatures get higher, magnesium, carbon and oxygen are released to form magnesium carbonate and dolomite (with calcium). They expand the rock in size, creating more pores and fractures. The chemical reaction also generates heat, making the process self-sustaining. Then the water exits, rises to the sea surface and absorbs more carbon dioxide, completing the convection cycle.

If the science works and it works on a large scale, then it'd be an economical partial solution to carbon emissions, but what about the money needed to pay governments to allow this kind of operation off their coast? Would it involve a global payment system or be incorporated into some permit trading system in some form similar to the CDM? Perhaps it could work like the reforestation mechanism in CDM (Clean Development Mechanism). The CDM was established by the UN following the Kyoto Protocol, which allows for the creation and trading of emission credits through the capture of greenhouse gas and reforestation, among others.

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Kelemen and Matter (2008) "In situ carbonation of peridotite for CO2 storage," Proceedings of the Nationa Academy of Sciences, 105(44)

PNAS abstract: http://www.pnas.org/content/early/2008/10/31/0805794105.abstract

Also at Technology Review: http://www.technologyreview.com/energy/21629/?a=f