eldavojohn writes "New research funded by the National Science Foundation at the University of Miami is showing that carbon dating (the 13C/12C ratio used to infer age) in the ocean can only be trusted up to 150 million years ago. From the primary researcher, 'This study is a major step in terms of rethinking how geologists interpret variations in the 13C/12C ratio throughout Earth's history. If the approach does not work over the past 10 million years, then why would it work during older time periods? As a consequence of our findings, changes in 13C/12C records need to be reevaluated, conclusions regarding changes in the reservoirs of carbon will have to be reassessed, and some of the widely-held ideas regarding the elevation of CO2 during specific periods of the Earth's geological history will have to be adjusted.' While this research doesn't necessarily throw carbon dating out the window, it should cause people to rethink so many theories about early life that revolved around ages of sediment in the oceans."