Sierra Eye: New techniques confirm blood of animal sacrifices on ancient African sculptures

Washington, Dec 2 : New diagnostic techniques used by chemists have confirmed the presence of blood from ritual animal sacrifices in the patina of ancient sculptures found in western Africa.
Patina is a coating of various chemical compounds such as oxides or carbonates formed on the surface of metals during exposure to weathering.
The study, which used new sensitive techniques like two types of mass spectroscopy and two methods of x-ray scanning, should yield a greater understanding of the practices of artists from long ago, and it could open the way for more detailed analyses of the world's most precious artefacts.
Anthropologists and ethnologists have uncovered much cultural evidence, from oral histories and illustrations, that ancient African artists often used ritual animal blood in their creations, generally as attempts to please or appease their deities.
In the empire of Mali, for example, which flourished from the early 13th century to the late 15th century C.E., the Dogon people decorated or painted their sculptures with various pigments thought to be composed partly of blood.
But, because of the age of the artefacts and lack of proper techniques, the composition of the patina had eluded standard chemical analyses.
Now, a team from the Centre for Research and Restoration of the Museums of France in Paris and other institutions in France has employed a quartet of new techniques to find out the presence of blood in the microscopic samples of the sculptures' coating.
"The techniques are so sensitive that they can detect even a few target molecules in a few micrograms of material, " said physical chemist Pascale Richardin, a co-author of the study. "They also offer the advantage that one technique can detect a desired molecule that the others might miss," he added.
In this instance, the measurements revealed the unmistakable presence in the patina of a form of iron associated only with blood, according to a report prepared by the research team.
"The research shows without doubt that the wooden figures were used in ceremonies involving animal sacrifice," said electro-analytical chemist Christian Amatore of the
École Normale Supérieure in Paris.
"Next up, is analysing the painting materials used by the masters of the European Renaissance--not to look for blood, but to attempt to reveal the secrets of their colours and textures," said Richardin.