Emilie Chalmin

Heating effect on manganese oxides used as black Paleolithic pigment

Manganese oxihydroxide behaviour has been studied under heat treatment to understand the transformation mechanisms and subsequently to gain insights into the preparation procedures of black painting materials during the Palaeolithic period. These manganese oxihydroxides have been studied as a function of heat treatment by TEM, XRD, DTA and FTIR and XANES (Mn K-edge) spectroscopies. These materials have been used as black pigments during the Palaeolithic period to realise rock art paintings such as in Lascaux (Dordogne, France) and Gargas (Midi-Pyrénées, France). Specific morphological, chemical and structural criteria were determined to distinguish between natural and heat-treated pigments.

Discovery of Unusual Minerals in Paleolithic Black Pigments from Lascaux (France) and Ekain (Spain)

Analyses of archaeological materials aim to rediscover the know‐how of Prehistoric people by determining the nature of the painting matter, its preparation mode, and the geographic origin of its raw materials. This study deals with identification of manganese oxides in black pigments by micro‐XANES (X‐ray absorption near‐edge structure) based on previous TEM (transmission electron microscopy) studies. Complex mixtures of the manganese oxides studied are present in some of mankind’s oldest known paintings, namely those from the caves of Lascaux (Dordogne, France) and Ekain (Basque country, Spain). Scarce manganese oxide minerals, including groutite, hausmannite, and manganite, were found for the first time in Paleolithic art at these archaeological sites. Because there are no known deposits of such minerals in these areas, more distant origins and trade routes are inferred. The closest known Mn‐rich geological province for Lascaux is the central Pyrenees, which is ≈ 250 km from the Dordogne area.

Fluorescence X-ray micro-spectroscopy activities at ESRF.

The X-ray Microscopy and Micro-analysis beamlines at ESRF operate complementary state-of-the-art instruments at ID21, ID22, ID18F and more recently ID22NI. Within a multi-modal strategy, these beamlines develop micro-imaging techniques with various contrast mechanisms (μXRF, μXANES, μXRD and phase contrast) and host experiments with scientific topics ranging from Geochemistry to Archeology, Environmental sciences, Biology and Material sciences. Future challenges include pushing spatial resolution down to the nano-scale and the development of innovative 3D micro-analysis techniques.