A new study by scientists has determined that a type of rock found at or near
the surface in the Oman and other areas around the world could be harnessed to
soak up huge quantities of globe-warming carbon dioxide (CO2).

Geologist Peter Kelemen and geochemist Juerg Matter, both from Columbia University’s
Lamont-Doherty Earth Observatory, made the discovery during field work in the Omani
desert, where they have worked for years.

Their studies show that the rock, known as peridotite, reacts naturally at
surprisingly high rates with CO2 to form solid minerals, and that the process
could be speeded a million times or more with simple drilling and injection methods.

Peridotite comprises most or all of the rock in the mantle, which undergirds earth’s
crust.

It starts some 20 kilometers or more down, but occasionally pieces are exhumed when
tectonic plates collide and push the mantle rock to the surface, as in Oman.

Geologists already knew that once exposed to air, the rock can react quickly with
CO2, forming a solid carbonate like limestone or marble.

However, schemes to transport it to power plants, grind it and combine it with
smokestack gases have been seen as too costly and energy intensive.

The researchers said that the discovery of previously unknown high rates of reaction
underground means CO2 could be sent there artificially, at far less expense.
“This method would afford a low-cost, safe and permanent method to capture and store
atmospheric CO2,” said Kelemen.

Their study area, a Massachusetts-size expanse of largely bare, exposed peridotite,
is crisscrossed on the surface with terraces, veins and other formations of whitish
carbonate minerals, formed rapidly in recent times when minerals in the rock reacted
with CO2-laden air or water.

Up to 10 times more carbonates lie in veins belowground; but the subterranean veins
were previously thought to be formed by processes unconnected to the atmosphere, and
to be nearly as old as the 96-million-year-old rock itself.

However, using conventional carbon isotope dating, Kelemen and Matter showed that
the underground veins are also quite young- 26,000 years on average-and are still
actively forming as CO2-rich groundwater percolates downward.

Many underground samples were conveniently exposed in newly constructed road cuts.
Kelemen and Matter estimate that the Omani peridotite is naturally absorbing 10,000
to 100,000 tons of carbon a year, which is far more than anyone had thought.

According to scientists, 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.

Source: ANI

Tags: atmosphere, atmospheric co2, carbonate minerals, carbonates, carbons, columbia university, containers, earth, energy, estimates, expanse, geochemist, geologist, globe warming, ground har, intensity, kelemen, lamontdoherty earth observatory, mantle rock, million times, natural, nature, peridotite, plants, power, power plants, rates of reaction, s, smokestack, tectonic plates, university, veins, water, world

This entry was posted on Thursday, November 6th, 2008 at 6:27 pm and is filed under RV Living. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.