After removing a surface layer, the internal part of the sample is gently crushed into powder and sieved.
If mortar has been sampled in dark light conditions in the form of powder, it can be directly sieved.
The aim of the study was to have diversified samples regarding age and geological origin, to look into differences between them and thence to draw more general conclusions concerning their dating potential.
The SG-OSL dating results presented in Table 1 refer to the mortar samples originating from the following archaeological monuments: List of studied monuments with corresponding historical periods, reference date intervals, reference dating methods, mortar function in masonry and sample numbers.
Also, sampling by scraping off has a drawback, since thin and thick sections of the sample cannot be prepared and material characterization is limited to chemical analyses of powder.
The sampling of mortars was performed in the zones attributed with certainty to the original constructions of each monument, avoiding restored or reconstructed areas.
Three categories of mortars were identified: samples without any exploitable SG-OSL signal, samples that could have been reliably dated and poorly bleached samples affected by microdosimetric variations whose dating still remains complicated.
Finally, the hypothesis on distinguishing between reliable and questionable dating results is raised and the potentials of the method for dating mortars are pointed out.
Apart from wide application in geology and sediment dating, optically stimulated luminescence dating (OSL dating) can also be employed to date architectural structures via the dating of construction mortars.
This specific application, based on the premise that quartz aggregate can be optically bleached during the mortar preparation, firstly appeared in literature in 2000 (B⊘tter-Jensen ., 2013).