When sedimentary rocks are exposed to the atmosphere, they can release CO2 that has been locked away for millions of years — likely to be a major player in the natural carbon cycle and influences atmospheric CO2 over thousands to millions of years.

Despite this recognition, this CO2 efflux is not well constrained, mainly due to lack of measurements of how fast this occurs and how the flux varies in space and time... Read more

Dr. Robert Hilton measures CO2 efflux from sedimentary rock in the Laval stream catchment, Draix, France. (© R. Hilton)