The cave paintings of Valltorta-Gassulla could be dated in absolute terms thanks to new analyses

The rock art of the Iberian Mediterranean Basin, also known as Levantine art, is a unique graphic expression within the recent European prehistoric framework and contains a wealth of information about the societies that painted it. Discovered in the early twentieth century, it was declared World Heritage by UNESCO in 1998 and its most distinctive features are that it is located in open-air rock shelters, that human figures have a dominant role in scenes portraying economic and social activities, and that red pigments largely prevail. However, the authorship and dating of this form of art found in the Iberian Mediterranean basin is still open to debate.

Most representations in Levantine art use a red pigment obtained from iron oxide, although other colours like black and white have occasionally been used. Red pigments have been present historically over time and are prevalent throughout the area of Levantine rock art. White pigments are not frequently used and in the Valltorta-Gassulla area they appear as a complement to the red colour to highlight the figures, to fill gaps or to add ornaments.

Black pigments are less common than red ones, but, in contrast to whites, their use is not limited to some temporal sequences or to particular geographical areas. In Valltorta-Gassulla, one of the most important areas in terms of the quantity and quality of painted shelters, very few representations in black were known so far. In this paper, researchers present a new set of figures in black, the identification of which had gone unnoticed in previous investigations. Clodoaldo Roldán explains that "up to now, these pigments were associated with the use of mineral components such as manganese oxides, but this study has made it possible, for the first time, to identify the use of carbonised plant material to produce the black pigments used in the Levantine paintings at Valltorta-Gassulla." Probably, these carbon-based black pigments are the most widely used in the history of humanity, because they can be used directly, without preparation, such as those from charcoal (vegetable carbon) or graphite (mineral carbon).

"The large number of figures painted with black pigments, used to draw both human figures and animals, and the subsequent changes to which these representations have been subjected, such as repainting or addition of new elements into the picture -- which would indicate a graphic and narrative re-appropriation -- make the Remígia cave an exceptional place for study," says Valentín Villaverde.

In the paper published in the Journal of Archaeological Science, these researchers present the new technical discoveries regarding the way to prepare and use black pigments in Levantine paintings. The fact of identifying black carbon-based pigments suggests the possibility of using carbon-14 dating, which represents an important step to solve the chronological controversy hanging over these prehistoric paintings ever since they were discovered.

For the study of the elemental composition of black pigments two types of analyses were used: on the one hand, the energy dispersive X-ray fluorescence (EDXRF), a non-destructive analysis made on site in order to preserve the integrity of the paintings; and, on the other hand, electron microscopy, a laboratory analysis of microsamples from a limited set of black figures. These techniques were applied to 34 points of black pigment and 18 points of non-black-pigmented surface. The points analysed are part of a total of 25 pictorial motifs among which there are 15 human figures, 6 animals, 1 animal track and 3 undefined motifs. Some of the black motifs described have undergone transformation processes such as a total or partial repainting in red. Such processes have not only modified the original shape of the figures, but the addition of new graphic elements has also led to a new interpretation of the story.

This research is part of the PROMETEO and PROMETEO II projects, funded by the Valencian government and led by Valentín Villaverde, and is financed with European funds under the Marie Curie Actions programme within the 7th Framework Programme of the European Research Council. The Cultural Heritage Service of the Valencian Department of Education, Culture and Sport has facilitated the investigations that have led to these remarkable discoveries.