Dating of zircons
There are two main types of detrital zircon analysis: qualitative analysis and quantitative analysis.
The biggest advantage of qualitative analysis is being able to uncover all possible origin of the sedimentary unit, whereas quantitative analysis should allow meaningful comparison of proportions in the sample.
It has become increasingly popular in geological studies from the 2000s mainly due to the advancement in radiometric dating techniques.
Basically analytical machines need to be calibrated before use.
Scientists use age-similar (comparable to the sampled zircons) and accurate zircons as their machine calibration standards.
Different calibration standards may give slight deviation of the resulting ages.
For example, there are at least twelve different standards catering for different sample zircons in Arizona Laserchron Center, primarily using Sri Lanka zircon, followed by Oracle.