Amongst the artefacts that have been found are ancient moa bones.
Some of these have been sent to the Waikato Radiocarbon Dating Laboratory for analysis.
It is during this stage that the carbon present in the sample is converted into carbon dioxide.
The carbon dioxide is collected and bubbled through various chemicals in the line, which purify it, and the amount of carbon dioxide that has been collected is measured.
The decay events for each sample are measured over a week.
The results from the liquid scintillation spectrometer are carefully analysed and provide a radiocarbon age for the sample.
This gas is then passed through a vanadium-based catalyst column, which produces liquid benzene (C).
A scintillator chemical (butyl-PBD) is added to the liquid benzene.
It is a long tube which is hooked up to a vacuum line.The silica glass vials are loaded into the liquid scintillation spectrometer.The C-14 atoms present in the benzene decay at a certain rate.To obtain a calendar age for the sample, this radiocarbon age needs to be compared against samples of known age by means of a calibration curve using a specially designed computer software application.This application uses a terrestrial calibration curve to calculate the calendar age.First, the lab will test the bone to see how much protein remains in it, because it’s the protein fraction of the bone that they actually date.Once they know that there is sufficient protein remaining, they clean the surface of the bone to remove contaminants like dirt, charcoal or, in some cases, glue that the archaeologists have used to mend the bone fragments The cleaned bone sample is then ground up into smaller pieces to speed up chemical reaction with the acid in the next stage.Fiona is wearing an aspirator because of the carcinogenic properties of benzene.Special silica glass vials are used to contain the mixture of benzene and PBD.The moa bone analysis gave a radiocarbon date of 580 plus or minus 40 years.Using the terrestrial calibration curve, a calendar age of AD 1390–1435 was established for the moa bone sample.