Contribution of LA-ICP-MS analysis to lead glaze investigation: two case-studies in medieval and modern archaeology

Emmie Beauvoit (1) , Florence Liard (1) , Rémy Chapoulie (1) , Bernard Gratuze (2) , Ayed Ben Amara (1)

1 IRAMAT-CRP2A - IRAMAT-Centre de recherche en physique appliquée à l’archéologie
2 IRAMAT-CEB - IRAMAT - Centre Ernest Babelon

Over the past fifteen years, electron backscatter diffraction (EBSD) coupled with energy dispersive X-ray spectrometry (EDS) have become routine analytical methods used on the scanning electron microscope (SEM) for exploring archaeological issues pertaining to glazing technology, to the use of pigments, and more broadly to decoration techniques of ancient ceramics. These approaches provide critical information on the microstructure and on the chemical composition of decorative materials. However, they have their limitations. They are not suitable for the detection of minor elements (<1%) nor for the detection of light chemical elements (Z<9) contained within the glazes. Therefore, for a thorough study of glazing technology, SEM-EDS analyses must be combined with other techniques. Laser ablation inductively coupled plasma – mass spectrometry (LA-ICP-MS) allows for an in-depth investigation of trace and light elemental composition of glazes.This poster illustrates two examples of a combined SEM-EDS and LA-ICP-MS analysis of archaeological lead-rich glazes. The first corpus consists of 150 samples of 12th- to 14th-century sgraffito tablewares from medieval Greece, for which SEM-EDS testings indicate the occurrence of tin- and antimonate-based pigments at the detection limit of SEM-EDS. The second corpus is composed of 80 samples of 19th-century white earthenwares from the Johnston-Vieillard manufactory in Bordeaux, France. SEM-EDS allowed us to determine that most glazes contain boron, but it did not enable us to quantify accurately concentrations in this light element (Z =5).The overarching aim of this research is to reconstruct raw material choices, glaze and recipes used for producing specific decorative styles; thereby offering further insights into craft traditions of the time. When combined with archaeological and historical investigation, such data is expected to further our understanding of how glazing technology was entangled into broader social and economic conditions shaping access to raw materials, learning between craftsmen, consumer tastes and demands.

Domaines: Archéologie et Préhistoire; Sciences de l'ingénieur [physics]

Emmie Beauvoit, Florence Liard, Rémy Chapoulie, Bernard Gratuze, Ayed Ben Amara. Contribution of LA-ICP-MS analysis to lead glaze investigation: two case-studies in medieval and modern archaeology. Annual Meeting of the Ceramic Petrology Group, Nov 2018, Tübingen, Germany. ⟨hal-01923078⟩