The radiocarbon dating method is based on the fact that radiocarbon is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen.The resulting radiocarbon combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire in a sample from a dead plant or animal such as a piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died.Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).
thus introduced takes a long time to percolate through the entire volume of the ocean.
The deepest parts of the ocean mix very slowly with the surface waters, and the mixing is uneven.
Research has been ongoing since the 1960s to determine what the proportion of in the atmosphere has been over the past fifty thousand years.
The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age.
The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.
Libby received the Nobel Prize in Chemistry for his work in 1960.
By contrast, methane created from petroleum showed no radiocarbon activity because of its age.
The results were summarized in a paper in Science in 1947, in which the authors commented that their results implied it would be possible to date materials containing carbon of organic origin.
radiation are similar to measurements for the rest of the biosphere.