Deutsch

Radiocarbon Dating Lime Mortar

[Print this Page] [E-mail this Page]

Two Ways to Date Lime Mortar

The following are listed in order of Beta Analytic's recommendations:

1 - Date the organic material extracted from lime mortar

Radiocarbon dating of this type is possible provided there is sufficient amounts of wood, charcoal or other plant remains that can be found. The accuracy will depend on what organic materials are extracted, and if they were contemporary to the time of the construction. If wood or charcoal found in the mortar was from "old" trees, then there will be "X" years bias in the result based on how old was the carbon in the trees.

2 - Date the lime mortar directly

It's also possible to date lime mortar directly but not usually from items exposed to the elements because the mortar will react with rain or groundwater to uptake carbon in the form of dissolved inorganic carbonates. Dating of lime mortar or plaster is very problematic and yields highly variable results even when the material has not been exposed to groundwater or rain water. For these reasons, we would not recommend dating the mortar directly, only organics recovered from it.

NOTE: Samples that date more recently than about 1650 AD produce multiple calibration ranges. This is due to their statistical overlap with the onset of the industrial revolution (and the release of large-scale fossil fuels) and above ground nuclear weapons testing of the mid 1950-1960 period.

Sample Sizes Required

AMS dating will be required for any samples sent due to the small amount of carbon that will be available. The lab needs between 1-4 mg of charcoal or 2- 5 mg of uncharred wood or plant post-cleaning and pretreatment and complete removal of the lime mortar by acid digestion. It's hard to know how much mortar is needed to be sent; it will depend on the amount of charred or plant material present in any one chunk of mortar.

If you would like to date directly the mortar or plaster, please call the laboratory or email us at lab@radiocarbon.com before sending your sample(s).

Submitting Samples

Please fill out our online form or send printed data sheets (pdf) together with the samples. There is no need to send the printed data sheets if you send sample details via our online form.

See detailed shipping instructions in our Send Samples page.