Natural Geologic Accumulations of CO2

For much of its history, the Earth has generated CO2 from molten rock deep in the ground. Learn more about the sources of geologic CO2. Volcanic eruptions have long helped transfer CO2 from deep in the earth to the atmosphere. Learn more about CO2 over time. Learn more about CO2 from volcanoes.

Halema'uma'u Crater at the summit of Kilauea Volcano in Hawaii by Steve Young.

Sometimes upward migrating geologic CO2 became trapped beneath an impermeable layer of rock and accumulated just the way oil and natural gas accumulates. Major natural underground accumulations of geologic CO2 have been found in the United States, Europe, and in other areas of the world.1,2 We know about these secure subsurface deposits of CO2 only because they were discovered during the search for underground deposits of oil and natural gas. In other areas the geologic CO2 accumulations are fractured or cut by faults and the geologic CO2 makes its way over time from these natural accumulations to the surface and then to the atmosphere.3 In a similar way, improperly sealed drill holes can act as conduits for geologic CO2. 3

In northeastern New Mexico, geologic CO2 from the Bravo Dome has been a source of CO2 for the manufacture of dry ice as well as the source of CO2 used for enhanced oil recovery (EOR) in the oilfields of West Texas. Learn more about the discovery, production, and usage of the Bravo Dome geologic CO2.

Secure, natural subsurface accumulations of geologic CO2 demonstrate that long-term storage of CO2 from human activities can occur if geologic conditions are appropriate.
  1. Stevens, S.H., Pearce, J.M., and Rigg, A.A.J., 2001, Natural analogs for geologic storage of CO2β€”an integrated global research program, in Proceedings of the 1st National Conference on Carbon Sequestration: Washington, D.C., May 15–17, 2001.
  2. Cassidy, M.M., Ballentine, C.J., Sherwood Lollar, B., Lawrence, J., 2007, Bravo Dome CO2 gas field, New Mexico, USA, and associated noble gases: type example of accumulation of carbon dioxide and window to the mantle: (accessed March 15, 2010).
  3. Zhou, Z., Ballentine, C.J., Schoell, M., Stevens, S.H., 2003, Noble gas tracing of subsurface CO2 origin and the role of groundwater as a CO2 sink, American geophysical union.
  4. Evans, J.P., Heath, J., Shipton, Z.K., Kolesar, P.T., Dockrill, B., Williams, A., Kirchner, D., Lachmar, T.E., and Nelson, S.T., 2004, Natural leaking CO2-charged systems as analogs for geologic sequestration sites, in Proceedings of the 3rd Annual Conference on Carbon Capture & Sequestration: Alexandria, Virginia, May 3–6, 2004.