Problems using carbon 14 dating gratis netdating Nyborg
You can get an idea of the relationship between C14 and age at the Carbon Dating calculator page. 1950 was chosen for no particular reason other than to honour the publication of the first radiocarbon dates calculated in December 1949 (Taylor, 19).
Ninety-five percent of the activity of Oxalic Acid from the year 1950 is equal to the measured activity of the absolute radiocarbon standard which is 1890 wood.
It is assumed that we are dealing with a closed system—no loss of either parent or daughter elements has occurred since the study material formed.
No scientist can guarantee that any sample can be considered a closed system unless it was isolated from its environment when it was formed.
A further example from a lava flow off the coast of Hawaii shows similar discrepancies.
If dated with the carbon-14 method, the flow appears to be less than 17,000 years old, but dating with the potassium argon method gives dates of 160,000 to 43 million years.
A copy of this paper may be found in the Radiocarbon Home Page The radiocarbon age of a sample is obtained by measurement of the residual radioactivity. T (National Institute of Standards and Technology; Gaithersburg, Maryland, USA) Oxalic Acid I (C). The activity of 1890 wood is corrected for radioactive decay to 1950.
This is calculated through careful measurement of the residual activity (per gram C) remaining in a sample whose age is Unknown, compared with the activity present in Modern and Background samples. Thus 1950, is year 0 BP by convention in radiocarbon dating and is deemed to be the 'present'.
Volcanic ejecta of Mount Rangitoto (Auckland, New Zealand) was found to have a potassium-40 age of 485,000 years, yet trees buried within the volcanic material were dated with the carbon-14 method to be less than 300 years old.
While there is no proof that the rates were different in the past than they are today, there is also no proof that they were the same.