A fragment of mortar from the pedestal ruin belonging to the central statue in Forum Vetus, Ulpia Traiana archaeological site, Romania, was investigated. The ruin is well-documented and unrestored, and radiocarbon dating was deemed suitable to determine its moment of construction. Preliminary analyses were used to establish the composition of the material and the sources of carbon-14, selecting the most reliable fraction for radiocarbon dating by the AMS method. Although sampling was carried out according to the recommendations, a younger apparent age was obtained than that expected. This is in fact a concrete-like mortar according to the analyses, and the phenomenon of delayed hardening of mortar in masonry was detected. The difference between the real and apparent ages quantifies this phenomenon. X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry with thermogravimetric analysis, and gamma spectrometry were used. Pyrogenic calcium carbonate and carbonates from calcium silicate/calcium aluminate hydrates were the only forms present in mini-nodules/lumps. The reactivation of binder calcite or geogenic calcite, the other problems encountered when dating mortars, were not spotted. This case study highlights the limitations of the radiocarbon dating method, and we introduce gamma spectrometry as a technique for additional investigations into direct exposure to the environment or the origins of raw materials.

Datarea radiocarbon prin metoda spectrometriei de masǎ cu ioni acceleraţi AMS, folositǎ din 2012 la IFIN-HH Mǎgurele, a oferit recent cadrul ştiinţific pentru un studiu interdisciplinar, atât din punct de vedere arheologic cât şi arheometric, aplicat unor materiale din lemn sau derivaţi ai lemnului. Primele rezultate radiocarbon calibrate obţinute pe şase eşantioane prelevate la Mǎguricea Branului în 2021 au plasat majoritatea probelor într-un interval în jurul secolului al XIII-lea, unele diferenţe putând fi explicate pe baza unor parametri ce sunt prezentaţi în acest articol. Cele patru probe similare suplimentare rezultate din campania 2022 au oferit date radiocarbon calibrate foarte diferite de estimǎri, dar şi faţǎ de cele anterioare. Deşi aceste probe au justificat dezvoltarea în laborator a unei metode noi de pre-tratare, pentru „lemn carbonificat”, unele rezultate nu au putut fi explicate din punct de vedere tehnic prin încadrarea în cei trei parametri: terminus post quem, time-width, apparent ages, aplicabili materialelor din lemn şi derivaţi, şi deci nu au putut oferi date relevante din punct de vedere arheologic. Lucrarea poate fi de interes pentru arheologii care folosesc probe de lemn pentru datarea AMS.

The stone Ensemble from Corbii de Piatrǎ Romania arouses a continuous scientific interest, with the final goal being to obtain an exhaustive and multidisciplinary package of results that will become the support of an extensive restoration project. The cave painting stands out as the most important and most affected by the advanced degradation among the historical monuments in Romania. This article provides for the first time a radiocarbon dating of the first forms of painting by establishing the age of the mortar/plaster used as a pictorial support. Being a very complex context from the point of view of the type of datable material and the disappearance over time through degradation of other elements that would ensure a simpler and more reliable radiocarbon dating (such as the straws used to form the material), it was necessary to use a multidisciplinary approach for the selection of samples and for supporting the radiocarbon results. The set of analyses consisted of visualization techniques through microscopy and compositional analysis, providing information on the similarities/differences between the samples, the degradation mechanisms/impurities and the quality of the calcium carbonate dated by the Accelerator Mass Spectrometry (AMS) technique. The results supported each other, ensured the selection of reliable radiocarbon data and established the most probable moment of the early interventions, namely the two phases corresponding to the 14th century.