ORAU > Dating services > Sample selection and identification

Sample selection and identification

Members of the unit are always happy to give advice on samples for radiocarbon dating. We have over thirty years of experience in the scientific aspects of the subject and have a staff who is able to deal with specifically archaeological or environmental questions. See the list of Staff for contact details.

Sample selection

Radiocarbon dating is a powerful technique but selection of the best samples for dating is essential to successful application. In all cases it is necessary to think about the relationship between the sample and the events of interest.

Despite its strengths, the resolution of radicoarbon dating is limited and so it is well worth checking the resolution of the method at different time periods by simulations using OxCal.

Sample selection

Materials and sample sizes

The choice of material for dating is an important part of any project and has a bearing on what kinds of statistical analysis will be possible at the end. It is always a good idea to discuss this with the laboratory if you are unsure.

Single entities (samples which originate from a single organism) are often the best type of sample for dating and in these cases identification to species or genus level is very useful. We can suggest people who may be able to help with this type of analysis.

Sample size is another constraint in selection of samples for dating. The following table shows some common material types and the typical ideal, and minimum sample sizes for analysis. In most cases it is possible to date even smaller samples but with considerably reduced precision and reliability.

Material Quantity Comments
Ideal Minimum
Bone, antler or ivory 600mg 100mg Depending on collagen preservation and method used
Charcoal or charred seeds 100mg 5mg Single seeds are often possible
Insect remains 50mg 5mg Depending on the methods used
Plant remains, cotton, linen or paper 100mg 20mg
Shells or other carbonates 50mg 15mg
Sediments 50mg 15mg Depends strongly on carbon content and fraction being dated
Silk, wool or hair 120mg 30mg
Wood 100mg 20mg

For more unusual samples the lab should be contacted before submission.

Materials for dating


The taking of samples is part of the dating service at ORAU and for many types of sample we would recommend either submitting objects to be sampled for return or visiting the lab so that sampling can take place on-site. In some cases we can sample on location.

In the case of samples that require specialist skills that we do not have in-house, such as the picking of forams, we can often put users in touch with those who have the relevant expertise.



The only restrictions on material accepted for dating are:

Sometimes, due to high demand for dating services, we are unable to date some types of sample. Please always contact the lab to discuss your project before submitting samples.

Graphite rigs

See sample submission.