2013 Volume 47 Issue 4 Pages 385-396
Basaltic aquifers have the potential to provide secure option for CO2 sequestration. Because basaltic rocks are widely distributed around the world, their capacity for storage of anthropogenic CO2 emissions is enormous. In addition, geochemical trapping of CO2 injected into basaltic aquifers occurs quickly, because basaltic rocks contain many cations that react with CO2 to form stable carbonate minerals. Two types of large-scale basaltic aquifers may be suitable for sequestering huge amounts of anthropogenic CO2: continental flood basalt aquifers and deep-sea basalt aquifers. Here, we assess the potential of these two CO2 sequestration options from geological, geochemical and social-scientific perspectives. From a geological and geochemical viewpoint, both continental flood basalt and deep-sea basalt aquifers have excellent CO2 storage potential. In deep-sea basalt aquifers, however, storage of injected CO2 may be more secure than in continental flood basalt aquifers, because leakage of CO2 to the atmosphere is minimized by geological, geochemical and physical barriers associated with the deep-sea environment. In addition, from a social-scientific point of view, several current CO2 injection projects in continental flood basalts have encountered problems due to groundwater depletion, and large-scale implementation of CO2 storage in continental flood basalt aquifers might cause contamination of freshwater resources needed for domestic and agricultural use. In striking contrast to continental flood basalts, deep-sea basalts can be used for CO2 storage without encountering critical problems, because deep-sea basalt aquifers have no economic value. We conclude, therefore, that deep-sea basalt aquifers are a better option for CO2 storage than continental flood basalt aquifers.