How far back can carbon dating go
The first calibration curve for radiocarbon dating was based on a continuous tree-ring sequence stretching back to 8,000 years.This tree-ring sequence, established by Wesley Ferguson in the 1960s, aided Hans Suess to publish the first useful calibration curve.It is also called “radiocarbon” because it is unstable and radioactive relative to carbon-12 and carbon-13.Carbon consists of 99% carbon-12, 1% carbon-13, and about one part per million carbon-14.Radiocarbon dating laboratories have been known to use data from other species of trees.In principle, the age of a certain carbonaceous sample can be easily determined by comparing its radiocarbon content to that of a tree ring with a known calendar age.Suess’s curve, based on the bristlecone pine, used tree rings for its calendar axis.There have been many calibration curves published since Suess’s curve, but their proliferation brought more problems than solutions.
The most popular and often used method for calibration is by dendrochronology.
Nowadays, the internationally agreed upon calendar calibration curves reach as far back as about 48000 BC (Reimer et.
al., INTCAL13 and Marine13 radiocarbon age calibration curves 0 – 50000 yrs cal BP, Radiocarbon 55(4), 2013).
For the period after 1950, a great deal of data on atmospheric radiocarbon concentration is available.
Post-modern data are very useful in some cases in illustrating a calendar age of very young materials (Hua, et. Atmospheric Radiocarbon for the period 1950-2010, Radiocarbon, 55(4), 2013).