Wiki radiometric dating
The mineral incorporates uranium and thorium atoms into its crystal structure, but strongly rejects lead.Therefore, one can assume that the entire lead content of the zircon is radiogenic, i.e.However, use of a single decay scheme (usually Pb) leads to the U–Pb isochron dating method, analogous to the rubidium–strontium dating method.Finally, ages can also be determined from the U–Pb system by analysis of Pb isotope ratios alone. Clair Cameron Patterson, an American geochemist who pioneered studies of uranium–lead radiometric dating methods, is famous for having used it to obtain one of the earliest estimates of the age of the Earth.By allowing the establishment of geological timescales, it provides a significant source of information about the ages of fossils and the deduced rates of evolutionary change.Radiometric dating is also used to date archaeological materials, including ancient artifacts.Radiocarbon dating is one kind of radiometric dating, used for determining the age of organic remains that are less than 50,000 years old.
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.Unraveling such complications (which, depending on their maximum lead-retention temperature, can also exist within other minerals) generally requires in situ micro-beam analysis via, say, ion microprobe (SIMS) or laser ICP-MS.Radiometric dating or radioactive dating is a technique used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed.Zircon is very chemically inert and resistant to mechanical weathering—a mixed blessing for geochronologists, as zones or even whole crystals can survive melting of their parent rock with their original uranium-lead age intact.Zircon crystals with prolonged and complex histories can thus contain zones of dramatically different ages (usually, with the oldest and youngest zones forming the core and rim, respectively, of the crystal), and thus are said to demonstrate inherited characteristics.
any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product.