If a rock has been partially melted, or otherwise metamorphosed, that causes complications for radiometric absolute age dating as well. Following the death of an organism, any exchange ceases and the carbon 14, which is radioactive and therefore unstable, slowly begins to disintegrate at a known rate half-life of years, ie, after this period only half of the total carbon 14 present at the time of death remains. Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages.
Scientists can use certain types of fossils referred to as index fossils to assist in relative dating via correlation. Why is it important to assume that the rate of radioactive decay has remained constant over time? Inotropic vs.