How accurate carbon dating
See also, on this website, articles on the ages of the geologic periods (Ages), radiometric dating (Radiometric dating), the reliability of radiometric methods (Reliability), a "time machine" for studying the distant past (Time machine) and the "uniformitarian" assumption and how it relates to evolution and the age of the Earth (Uniformitarian). ’s free newsletters."data-newsletterpromo-image="https://static.scientificamerican.com/sciam/cache/file/458BF87F-514B-44EE-B87F5D531772CF83_source.png"data-newsletterpromo-button-text="Sign Up"data-newsletterpromo-button-link="https:// origincode=2018_sciam_Article Promo_Newsletter Sign Up"name="article Body" itemprop="article Body" magazine The carbon clock is getting reset.
But, as is clear even from the very brief discussion in the previous paragraph, radiocarbon dating can say nothing one way or the other about whether the Earth is many millions of years old, since such dates are far beyond this method's range of resolution.
Comparing these counts with a series of 651 radiocarbon-dated samples spanning this record, they obtained a calibration curve that is very close to the 2009 calibration shown above [Callaway2012]. It should be emphasized that the actual calibrated dates are about 10%-20% older than the raw uncorrected radiocarbon dates that were once used.
Compare, for example, the uncorrected line (blue dotted line) with the calibration curve (red curve).
For instance, even in the 1950s, when Willard Libby first developed the process, it was recognized that the scheme assumes that the level of carbon-14 in the atmosphere is constant.
But researchers have known at least since 1969 that the carbon-14 level has not been constant, so that the radiocarbon clock needs to be "calibrated." As a result, various schemes are used to correct and calibrate radiocarbon dates, including: In each case, radiocarbon dates, determined by well-established procedures and calculations, are compared directly with dates determined by the above methods, thus permitting the radiocarbon dates to be accurately calibrated with distinct and independent dating techniques.