The Long Island Press reported recently on a recent paper in the Proceedings of the National Academy of Sciences which points to extensive deposits of basalt off the coasts of Long Island, New Jersey and Massachusetts as a possible repository for carbon dioxide emitted by coal and waste-burning power plants.

The authors of the study, based at Columbia University's Lamont-Doherty Earth Observatory, estimate that a small patch of the volcanic rock near New Jersey's Sandy Hook could accommodate close to a billion tons of CO2 - the equivalent of the emissions from four billion-watt coal-fired plants over 40 years.

Carbon sequestering -- the idea that carbon dioxide emissions can be trapped and prevented from entering the earth's atmosphere -- has caused controversy in recent years, partially because many believe that existing storage techniques such as injecting the gas into deep aquifers or depleted oil and gas reservoirs are susceptible to leakage.

The study's authors claim that the deep-sea basalt deposits offer a superior depository for several reasons. First, basalt is full of pores leaving ample room to pump in liquefied CO2, which would displace only sea water. Second, the deposits lie at least 2,500 feet below sea level, deep enough that water pressure and sediment would prevent liquid CO2 from returning to a gas form and floating to the surface. Third, the CO2 would react with the basalt to form a stable, harmless, limestone-like mineral.

Using seismic and gravity measurements, the study estimated that there are four basalt deposits of more than 1,000 square kilometers each off the East Coast, but recommend drilling to get more precise data.

Opponents, such as Emily Rochon of Greenpeace worry that funding for carbon sequestering will siphon off funds that would be better spent on renewable energy technology.