Les pigments et les parois des grottes préhistoriques ornées

Abstract

Until recently, physicochemical research on rock art was principally focused on the study of artistic records of the Palaeolithic culture. It involved the identification and the elemental and chemical characterisation of the pictorial matter. The considerations about the mechanisms responsible of taphonomic alterations of cave walls came later, as an answer to the challenges raised by the preservation of rock art and archaeological records. However, the studies, dealing with these two approaches in a same thinking, are still rare. These could enable a better appreciation of the pigment-wall interactions, given back in their global environmental context. By taking benefit of the technological progress in the field of X-ray and laser sources, as well as detectors, analytical systems were miniaturised and became transportable. It facilitates their direct application in the field. It opened up new prospects on acquiring statistically relevant data for archaeological on-site interpretation, while preserving the integrity of the archaeological records. The difficult conditions specific to cave environments (humidity, temperature, difficult access to the caves and to the decorated panels) make these in situ physicochemical analyses challenging. The manufacturing of self-built portable spectrometers, more adapted to these difficult environments, led to a renewal of the physicochemical analyses of rock art. The work engaged in the Rouffignac cave (Dordogne) benefited from these technological improvements. It enabled to develop an approach combining the study of the pigments used, the evaluation of the state of the decorated surfaces over time, and the relation between pigment and wall support.

Keywords

• taphonomic processes
• wall art
• XRF
• XRD