Identification of organic binders in pre-historic pigments through multiproxy archaeometric analyses from the Toca do Paraguaio and Boquerao da Pedra Furada shelters (Serra da Capivara National Park, Piauì, Brazil)

Pigments from several pre-Historic rock art painting samples were analysed through a multiproxy archaeometric approach. Sampling occurred in two rockshelters within the National Park of Serra da Capivara National Park area (a UNESCO World Heritage Site): Toca do Paraguaio and Toca do Boqueirão da Pedra Furada. Five complementary techniques x-ray micro-fluorescence, Raman spectroscopy, scanning electron microscopy, stereomicroscope observation and high temperature-gas chromatography (HT-GC) were combined to identify and characterise the inorganic and organic material. In particular, gas-chromatography analyses revealed the presence of binders, hardly recognised in rock art pre-Historic pigments. These binder substances (plant fatty acids) could be included in the pigment process ‘chain-opératoire’.