After seven years the radiocarbon dating scale got an upgrade and it will have major implications in the field of archaeology. A group of researchers led by scientists at the University of Cambridge just released IntCal20. The IntCal is the name for the radiocarbon dating scale that is most widely used and the 20 represents the 2020 update.
What is Radiocarbon dating?
Upon discovery, scientists approximate the age of artifacts. The age of an artifact can be determined by relative or absolute methodologies. Relative methods rely on comparing the discovery location with other objects found in similar sedimentary layers or areas to give an age approximation; or absolute methods that use the law of radioactive decay to estimate age. One of these absolute methods is radiocarbon dating.
only relevant to organic artifacts.
The law of radioactive decay states that the probability per unit time that a nucleus will decay is a constant, independent of time. Simplistically, this means is once something dies, isotopes of elements like carbon will degrade at the same rate regardless of the age of the artifact.
Due to this principle, scientists are able to measure the concentration of carbon isotopes present in a material. After the measure a concentration of the carbon 14 isotope they can compare it to an aggregated data set of reference points for carbon 14 content and known age. Comparing the carbon 14 concentration of the unknown artifact to artifacts with know ages allows scientists to approximate the age of the newly discovered artifact.
How the IntCal Works
The scale used to determine the date of artifacts is called the IntCal and the first iteration of it was published in 1998. The IntCal was not the first scale used for radiocarbon dating, however after its advent in the 1990’s it has become the golden standard.
The basic working principle of the radiocarbon dating scale is to use a curve generated from reference points. These reference points are materials that we know the age of and we can measure their carbon 14 content. Scientists collect a bunch of these reference points and graph them to create a calibration curve. Some of the most widely used reference points are actually tree rings.
for the development of the IntCal scale.
After a calibration curve is created, scientists use that calibration curve on materials that they don’t know the age of and estimate their age based on the amount of carbon 14 still present.
Updates and Limitations of the Radiocarbon Dating Scale
Prior to this recent update, IntCal20 after something was over 50,000 years old radiocarbon dating was not reliable. Additionally, pinpointing the exact age of something within that 50,000-year window was harder. Both of these issues stem from a lack of reference points. The first is a result of not enough reference points at the years above 50,000. The second because fewer reference points mean that there is a broader range that an amount of carbon detected represents.
In order to address these limitations scientists will actively seek out additional reference points. Each update adds additional reference points. The IntCal20 update addressed both of the limitations mentioned earlier. With the incorporation of additional reference points above 50,000 years, we are now able to date things back 55,000 years. And with more reference points within that 55,000-year range the age range an amount of carbon represents shrank as well. This update allows scientists to be more accurate when they date objects. This update will not only have an effect on newly discovered artifacts but also improve the accuracy of previously discovered artifacts’ ages.
If you have more interest in learning about the IntCal updates you can check out the scientific article here.