Yellowstone sinter research article graphic representing sample col...
Graphical abstract of the new research paper. The scientists collect samples from the rocks forming near hot springs and geysers. They dissolve small amounts of the rock in acid and organic carbon (created by living organisms) remains behind. The ratio of 14-Carbon to 12-Carbon reflects how long it has been since the organisms were living (and took in 14-Carbon from the atmosphere). This provides an age estimate of the growing sinter deposit.
Lowenstern et al., 2016