14c12c ratio carbon dating
Used to calculate the fractionation correction in radiocarbon dating.
δ 14C: The 14C isotopic ratio of a material relative to the modern standard, without any correction for fractionation.
The modern standard activity is defined for 1950, so measurements made at a later time must correct the measured oxalic activity for decay since that year.
Radiocarbon ages are inferred from the measurements subject to a number of assumptions and qualifications. Cosmic Ray: The high energy atomic radiation that bombards the earth from space.Conventional Radiocarbon Age (CRA): The age obtained from a radiocarbon measurement using conventions set out in a paper by Stuiver & Polach (1977).This is not the true chronological age of the sample, which is obtained by calibrating the conventional age.1990, without a decay correction Fractionation: The change in isotopic ratio that can occur when a material undergoes a chemical reaction or certain types of physical processes.Although the different isotopes of an element are said to have identical chemical properties, the rate at which they take part in a chemical reaction depends on their mass.