Thermal behaviour of organic radicals and paramagnetic centres in chert: A case study of Bergeracois brown chert, Dordogne, France

In order to successfully understand the complex evolution of prehistoric societies, archaeologists require absolute dating tools, which are not only accurate but also widely applicable. Thermoluminescence (TL) dating is one such approach that has been successfully used to establish a general chronological framework for prehistoric sites and is particularly suited for use on heated lithic artefacts. Experiments conducted in this study have clearly shown the applicability of Electron Spin Resonance (ESR) isothermal modelling in combination with TL dating to constrain firing temperature. This expands the potential application for TL dating to include artefacts treated at low firing temperatures. The present study shows potential in terms of precision and accuracy for framing the “equivalent firing temperature”. At the same time, the comparison of the TL signal with the lattice-defects and aluminium centres invigorate the use of ESR dating on heated flint, especially with samples that have received low thermal treatment. The presence of organic matter in large quantity raises concern on the pyrolysis effect on the luminescence signal; however, the use of ESR isothermal and isochronal modelling could potentially lead to the ability to overcome current interferences of the organic radicals within the dating signal of TL.

Thermoluminescence Analysis of the Clay Core of Bronze Statues: A Re-Appraisal of the Case Studies of Lupa Capitolina and Other Masterpieces in Rome

In this work, we present some new results in applying thermoluminescence (TL) dating to the clay core of bronze statues. This is very important, due to the impossibility of directly dating a metal. Very few cases of indirect dating of clay cores by TL are reported in the literature. We re-considered three cases of dating of clay core from important bronzes in Rome. The parameters to be considered were not easy to calculate in the case of the Lupa Capitolina. However, its traditionally reported Etruscan origin is definitely ruled out, even if the accuracy in the dating is too low to precisely propose a date of the casting. The comparison with radiocarbon results shows good agreement for a Medieval dating. Two other bronze statues were analysed in order to date their casting by TL; a horse from Musei Capitolini resulted to have been cast in the Greek classical period, excluding its casting in the Rome imperial period. A third study shows that, in particularly favourable situations, TL dating of clay core can give rather precise results. This is the case where in the clay core are present materials that behave like good dosimeters, as generally happens in dating ceramics. Furthermore, the possibility of measuring all the parameters influencing the calculation of the dose rate is essential; both the external radiation sources and the radiation reduction by the water content must be taken into account. This was the case of Saint Peter in the Vatican that turned out to be a cast from the beginning of the XIV century.

New data on the age of the Middle Palaeolithic site of Proniatyn (Podolian Upland)

The Middle Palaeolithic site Proniatyn is geomorphologically located on the near-watershed slope of the right bank of the Seret River. The history of its archaeological research began in 1977. During numerous expedition seasons of works conducted with using of methods of natural sciences and archaeology (until 2015), rich flint material was found on the site, which was located in the deposits of the over-Horokhiv deluvial solifluction stratum, i.e. not in situ, but was moved down the slope. The upper chronological limit of the cultural horizon was determined as 85±7 ka (according to V. Shovkoplias) by TL-dating of the Upper Pleistocene loess, which overlaps the over-Horokhiv deluvial solifluction stratum. In 2015, the Proniatyn site became the subject of scientific excursion of the international loess seminar «Loesses and Palaeolithic of Podillia». To clarify the age of the site, survey pit 5, located directly next to the main excavation, in the southern part of the site was expanded and deepened. The main goal of the work was to search for artifacts in the Horokhiv fossil pedocomplex (MIS 5), which is only slightly disturbed by deluvial-solifluctional processes. Two artifacts were found in the eluvial horizon of this complex, the third one was found in its humus horizon. Detailed analysis of the finds shows that the additional flint artifacts discovered in 2015 do not contradict the conclusion that technical, morphological and typological features of these three flints are completely identical to several thousand previously excavated flints from this site and represent the flake-blade Levallois industry. In general, all discovered artifacts from Proniatyn form a single monocultural complex of the site. Based on research conducted in 2015 is clearly established that the age of Proniatyn cultural horizon does not correspond to the age of deluvial-solifluctional strata, as previously thought, but is older than it. It is associated with the eluvial horizon of the Horokhiv fossil soil complex, the age of which is estimated at 112,0±11,2 ka and 106,7±11 ka according to TL-dating (the Palaeolithic site Yezupil I), 110±18 ka according to TL-dating and 102±16 ka according to OSL-dating (Palaeolithic site Mariampil I). Key words: Middle Palaeolithic, artifact, Mousterian, loess-palaeosol sequence, deluvial-solifluctional processes, Podillia.

CW-OSL, LM-OSL and TL dating of bricks from Karakorum, Mongolia: Insights from TL spectra

In this study, we present results of luminescence dating using CW-OSL, LM-OSL and TL on heated quartz from the archaeological and historical site in Karakorum – the ancient capital of Mongolia, to test their convergence with the age control in the form of the Karakorum inscription 1346. The TL spectra conducted on quartz from red and grey coloured bricks appeared to be characteristic of the technological origin. Quartz TL from red bricks showed a UV emission band at ~360 nm and a strong fast OSL component dominated signal. In contrast, blue emission detected in the TL spectra of grey coloured bricks, resulting possibly in the medium component dominated OSL signal. Finally, OSL and TL results gave dates from 1180±70 AD to 1360±70 consistent with the expected ages.

Origin of a silver Stollhof-type disc excavated at Vanovice (South Moravia)

The oldest silver artefact from north of the Alps was found on the territory of Czech Republic is Stollhoff-type disc found in Kotouč hill near Štramberk. Similar silver disc was recently excavated at Vanovice (Czech Republic). This paper was complied to answer these particular questions: 1. what was the origin of earliest silver artefacts in Central Europe, 2. when these artefacts were emerged, and 3. what raw material was used and how it was processed. To answer these questions, typological analysis of vessels, thermoluminescence (TL) dating, compositional analysis (performed by ED-XRF) and scanning electron microscopy were employed. According to shape of ceramic vessels accompanying silver artefact, the Vanovice hoard can be dated to the Baalberge phase of the Funnel Beaker Culture during the later Eneolithic. Attempt to date pottery by TL method was not successful. The local origin of the pottery and the Carpathian/East-Balkan source of metal suggest that the Vanovice silver disc and the accompanying pottery were made in different periods, largely because precious metals endure longer than pottery.

Integrated Dating of the Construction and Restoration of the Modena Cathedral Vaults (Northern Italy): Preliminary Results

ABSTRACTAfter the last damaging earthquake in 2012, an anti-seismic reinforcement project of the cathedral of Modena was designed giving us the opportunity to investigate and date the building materials. Radiocarbon (14C), optically stimulated luminescence (OSL), and thermoluminescence (TL) dating techniques were performed on the vaults with the aim to (1) clarify the construction timing, (2) define the history of the restorations, and (3) explore the possible correlation of the main restoration works to the earthquake chronology deduced from the historic catalog. Preliminary results show that medieval older bricks were reused for most of the original construction. Only lime and non-gypsum mortar was used for the original construction in the 15th century and for later repair of damage caused by earthquakes in the 16th and 17th centuries. Gypsum mortar was used for later repair in the 18th century. The results show much stronger damage due to earthquakes than previously thought.

Mississippian Origins as Viewed from the Shiloh Indian Mound Group, Western Tennessee

The Shiloh Indian Mound Group has produced a number of artifacts that appear to derive from the American Bottom area. Radiocarbon and TL dating indicates the site was occupied from the late tenth through early 14th centuries AD, with construction activity at Mound A occurring between approximately AD 1100 and 1340, with major stages erected during the early and mid-13th century. The Shiloh center was thus emerging during Cahokia’s Stirling phase, from ca. AD 1100–1200, and reached its peak during the subsequent Morehead Phase, from AD 1200–1300. Shiloh, like Cahokia itself, was abandoned sometime around AD 1300. Shiloh’s Mississippian center apparently emerged amid local Late Woodland peoples who apparently made little prior use of the location, suggesting an amalgamation of differing populations or social groups, much as Cahokia itself was likely formed.