Definition of chronometric dating
Definition of chronometric dating - Online sex
It measures the decay of radioactive carbon (14C) that has been absorbed from the atmosphere by a plant or animal prior to its death.Radioactive carbon has a half-life of approximately 5,730 years plus or minus 40 years (1 standard deviation of error) and the theoretical absolute limit of this method is 80,000 years ago, although the practical limit is close to 50,000 years ago.
Stratigraphic dating is based on the principle of depositional superposition of layers of sediments called strata.This principle presumes that the oldest layer of a stratigraphic sequence will be on the bottom and the most recent, or youngest, will be on the top.The earliest-known hominids in East Africa are often found in very specific stratigraphic contexts that have implications for their relative dating.The majority of chronometric dating methods are radiometric, which means they involve measuring something related to radioactivity, for example radioactive decay.Relative dating methods allow one to determine if an object is earlier than, later than, or contemporary with some other object.It does not, however, allow one to independently assign an accurate estimation of the age of an object as expressed in years.
The most common relative dating method is stratigraphy.
Other methods include fluorine dating, nitrogen dating, association with bones of extinct fauna, association with certain pollen profiles, association with geological features such as beaches, terraces and river meanders, and the establishment of cultural seriations.
They are called chronometric because they allow one to make a scientific estimate of the date of an object as expressed in years.
They do not, however, give "absolute" dates because they merely provide a statistical probability that a given date falls within a certain range of age expressed in years.
Chronometric methods include radiocarbon, potassium-argon, fission-track, and thermoluminescence.
The most commonly used chronometic method is radiocarbon analysis.