Communication with clients also gives labs an idea of the possible types of contaminants in the excavation site. The sequence can be compared to the calibration curve and the best match to the sequence established. University of Arizona. Before the advent of radiocarbon dating, the fossilized trees had been dated by correlating sequences of annually deposited layers of sediment at Two Creeks with sequences in Scandinavia. This was demonstrated in by an experiment run by the British Museum radiocarbon laboratory, in which weekly measurements were taken on the same sample for six months. There are two types of testing technology: The reliability of the results can be improved by lengthening the testing time.
For example, from the s questions about the evolution of human behaviour were much more frequently seen in archaeology.
Radiocarbon Dating and Archaeology
This led to estimates that the trees were between 24, and 19, years old,  and hence this was taken to be the date of the last advance of the Wisconsin glaciation before its final retreat marked the end of the Pleistocene in North America. As a tree grows, only the outermost tree ring exchanges carbon with its environment, so the age measured for a wood sample depends on where the sample is taken from. The sample-context relationship is not always straightforward. The unstable and radioactive carbon 14, called radiocarbon, is a naturally occurring isotope of the element carbon. To produce a curve that can be used to relate calendar years to radiocarbon years, a sequence of securely dated samples is needed which can be tested to determine their radiocarbon age. In addition, if a piece of wood is used for multiple purposes, there may be a significant delay between the felling of the tree and the final use in the context in which it is found.