(Fossil-bearing sedimentary rock cannot be directly dated radioisotopically.) Second, the date of formation of the dacite is known.Lloyd Anderson, far right, takes home-schooled children on a tour of the land around Mount St.Plants absorb that carbon through photosynthesis, and animals via plants.When they die, however, the radioactive carbon decays at a known rate.It is one of those rare days when the weather in southwest Washington clears so you can see Mount St.Helens, which rises behind Anderson and his joyous grin.
The atmosphere contains trace amounts of radioactive carbon (14C).Helens, pointing out geologic structures formed by the volcano’s eruption in 1980 that young-Earth creationists say support their beliefs.“Look! ” Lloyd Anderson springs ahead of the small group of visitors he has been leading through Gifford Pinchot National Forest.Reaching a small observational clearing, he sweeps his arm toward the horizon and bounces with excitement as he waits for the group — Forest Carnine, a cattle rancher from Angora, Neb.; his wife, Dorothy; their daughter-in-law, Ingrid Carnine of Boring, Ore.; and her two young sons — to catch up.Measuring the ratio of radioactive to stable carbon, we can estimate the age of carbon-bearing samples.On the other hand, the technical details of radiocarbon analysis are difficult to understand.