# Radioactive decay and radiometric dating

We can also construct a Concordia diagram, which shows the values of Pb isotopes that would give concordant dates.The Concordia curve can be calculated by defining the following: ).Since the exact rate at which uranium decays into lead is known, the current ratio of lead to uranium in a sample of the mineral can be used to reliably determine its age.

Although we now recognize lots of problems with that calculation, the age of 25 my was accepted by most physicists, but considered too short by most geologists. Recognition that radioactive decay of atoms occurs in the Earth was important in two respects: Principles of Radiometric Dating Radioactive decay is described in terms of the probability that a constituent particle of the nucleus of an atom will escape through the potential (Energy) barrier which bonds them to the nucleus.The term U–Pb dating normally implies the coupled use of both decay schemes in the 'concordia diagram' (see below).However, use of a single decay scheme (usually Pb) leads to the U–Pb isochron dating method, analogous to the rubidium–strontium dating method.Where crystals such as zircon with uranium and thorium inclusions do not occur, uranium-lead dating techniques have also been applied to other minerals such as calcite/aragonite and other carbonate minerals.These types of minerals often produce lower precision ages than igneous and metamorphic minerals traditionally used for age dating, but are more common in the geologic record.