Dating of zircons
The objective and scale of the research project govern the type and number of samples taken.In some cases, the sedimentary rock type and depositional setting can significantly affect the final result.
It is common to have sub-rounded/rounded detrital zircons as opposed to prismatic igneous zircon.
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.
Depending on the degree of physical sorting, mechanical abrasion and dissolution, a detrital zircon grain may lose some of its inherent features and gain some over-printed properties like rounded shape and smaller size.
On a larger scale, two or more tribes of detrital zircons from different origins may deposit within the same sedimentary basin.
Different calibration standards may give slight deviation of the resulting ages.