SCIENCE IN THE SERVICE OF ARCHAEOLOGY

Dating of archaeological samples provides objective chronological information for organic materials (wood, charcoal, bones, seeds, plant residues, peat…) by carbon-14 or radiocarbon dating, for heated minerals (terracotta, brick, hearthstone, heated flints…) by thermoluminescence (TL), and for exposed sediments by optically stimulated luminescence (OSL).

CIRAM has been working for years with the best scientists to ensure an optimal response to archaeological problems. Thanks to our state-of-the-art radiocarbon dating laboratory, we offer precise expertise adapted to your needs.

CIRAM is a specialist in the dating and analysis of archaeological and heritage materials.

Analytical methods for archaeological materials

Archaeometry groups together the various physico-chemical analysis techniques used for the characterization of all types of mineral and organic materials uncovered during archaeological excavations. We can identify the chemical composition of organic residues, determine the crystallographic nature of a terracotta, define the origin of a raw material, find the diet of an individual and population movements. Archaeometry also includes carbon-14, thermoluminescence (TL) and optically stimulated luminescence (OSL) dating techniques.

Archaeology and the discovery of remains

Archaeometry is the preferred scientific partner of archaeology. CIRAM generally intervenes on preventive archaeology excavation sites. But, we also provide dating and analysis services during programmed archaeological excavations. CIRAM will adapt these analytical methods to the typology of the artefacts unearthed. Examples include carbon-14 or radiocarbon dating, thermoluminescence (TL) and optically stimulated luminescence (OSL) dating, isotopic analysis, or examination of organic residues.

Carbon-14 dating, the star of archaeometry

Carbon-14 dating is the main archaeometric service performed by CIRAM. This method has the advantage of being able to date all organic materials, such as wood, charcoal, bones, teeth, seeds, peat, organic residues, but also mortar or shells.

Carbon 14 dating, also called radiocarbon dating is based on the measurement of the 14 isotope of carbon still present in a material. Our doctors and engineers measure the residual concentration of carbon 14 by AMS (gas pedal particle coupled to a mass spectrometer). Carbon-14 dates the death of the individual or organism.

Because each archaeological artifact is different, our scientific teams conduct a protocol based on the type of material. For example, charcoal will undergo chemical pre-treatment (ABA), to remove potential pollutants and extract cellulose. Whereas bones or teeth will be treated differently, since the collagen will be extracted. It’s the organic part of the bone, the collagen, that’s going to be carbon 14 dated.

Our carbon 14 dating lab offers a 10-business day turnaround. We provide raw ages, but also calibrated dates. The dating results are compiled and commented on in an analysis report that is sent to you in electronic form. In addition, we are committed to discussing and explaining the dating results with archaeologists.

Isotope analyses

Carbon-14 dating is not the only technique in archaeometry. Stable isotope analysis of carbon, nitrogen, sulfur, and strontium provides many answers to archaeological problems. The isotopes of carbon, nitrogen and sulfur will provide information on the diets of the populations. Was it a meat diet? Were the animal proteins of terrestrial or marine origin? Strontium isotopes will provide information on population movements and the origin of individuals. Stable isotope analysis of carbon, nitrogen, sulfur, and strontium is performed on bones and teeth.

Analysis of organic residues

Many archaeological artifacts contain food or drink remains, cooking remains, and cosmetics. These organic residues are more or less well preserved in amphorae, clay pots, metal containers. The analysis of archaeological organic residues will allow the identification of diets, cooking habits, exchanges of raw materials, and local production. The analysis of organic residues is carried out by Fourier Transform Infrared Spectrometry (FTIR – ATR) or by pyrolysis coupled with gas chromatography and a mass spectrometer (Py – GC – MS). These techniques allow us to identify the organic molecules present and to trace the nature of the food, drink or cosmetic product for example.

X-ray imaging – 3D tomography

Our specialists also examine archaeological artifacts with non-destructive methods (X-ray radiography and 3D scanning). These scientific imaging techniques reveal the state of preservation of metallic artifacts, reveal the presence of metallic elements inside a gangue, or perform a virtual excavation of a funerary urn with the 3D CT scanner. CIRAM has a digital and portable X-ray radiography, which allows on-site intervention and the obtaining of X-ray images in real time.

The instantaneous analysis of X-ray radiographs offers the possibility of adapting the analytical procedure in real time and acquiring images from the most relevant viewing angles, with the most appropriate experimental parameters. It thus allows an optimal interactivity with the archaeologists who can direct the study as they wish. The 3D tomography or CT scanner will allow to visualize in three dimensions the homogeneity of an object, its state of conservation or to identify manufacturing techniques, and to carry out, if necessary, a virtual excavation.

Anthracology and xylology

Our expertise is not limited to carbon-14 dating and we are not satisfied with using ultramodern machines. Wood analysis, xylology, and charcoal analysis, anthracology, are also part of the wide range of scientific analysis that CIRAM offers. From the Greek xylos (wood) and logos (speech), xylology studies the physical and chemical properties of wood in order to identify their species. By making it possible to know the trees available to craftsmen and the choices they made for the realization of their works, xylology makes it possible to reconcile a hypothesis of geographical origin with the map of the species’ location.

The objectives of an anthracological study are to identify the species of wood and to characterize the charcoals, in order to reconstitute the botanical environment of the period and to better understand the uses of the material by human societies. Anthracology is also essential to determine the origin of the samples (heartwood, branch/twig), in order to avoid the “old wood” effect for carbon 14 dating. After refreshing the surfaces with a razor blade, the anatomical analysis of the charcoal is carried out along three axes: transverse, tangential and radial. Observation of the anatomical elements along these three axes will allow determination of family and genus, as well as species in the best case.

CIRAM, world leader in dating

Thanks to its laboratories and teams of scientists, CIRAM is a world leader in the dating of organic and mineral archaeological artifacts, specializing in carbon-14 (C14), thermoluminescence e (TL) and optically stimulated luminescence (OSL) dating.

With no less than twelve staff members specializing in archaeometry, archaeology, materials analysis, and dating, we are equipped with next-generation equipment to study archaeological artifacts and heritage objects.