Non-destructive provenance differentiation of prehistoric pigments by external PIXE

The elemental analysis of minerals/rocks has been often used for the determination of their geological origin. When these natural rocks were exploited by prehistoric civilizations as objects, weapons, or pigments, the composition of the minerals can provide information on the mobility, the exchanges and the interaction between groups of population. In this paper, we will present results obtained from archaeological samples of prehistoric pigments, mainly iron and manganese oxides. PIXE analysis has been applied to samples of the prehistoric cave La grotte du Renne in Arcy-sur-Cure, France (Chatelperronian, 38,000-34,000 BP). Because most of the archaeological objects are decorated or display some use marks, it is not possible to take samples. Consequently, we have used a non-destructive technique thanks to the external beam of AGLAE (C2RMF, Paris). In order to improve the limits of detection (LOD less than 10 ppm from Cu to Sb), a metal absorber has been placed on the X-ray detector to preferentially filter the Fe-K or Mn-K lines. Based on the quantitative analysis of major and trace elements, we have obtained groups of compositions corresponding to different geological sources. We demonstrate in this study that it is possible to extend PIXE analysis to the characterization of prehistoric pigments such as iron and manganese oxides for differentiating potential sources of pigments in archaeological contexts. (C) 2011 Elsevier B.V. All rights reserved.