Characterization and origin of black and red Magdalenian pigments from Grottes de la Garenne (Vallée moyenne de la Creuse-France): a mineralogical and geochemical approach of the study of prehistorical paintings

International audienceRemains of pictorial decorations in a series of six representative megalithic monuments of Brittany (France) and two French stelae have been studied by micro-Raman spectroscopy for the first time. Fungal colonies on the painted orthostats made it difficult to obtain in situ Raman spectra of the paint components. Nevertheless, paint micro-specimens studied in the laboratory by micro-Raman spectroscopy, X-ray photoelectron spectroscopy and scanning electronic microscopy combined with energy dispersive X-ray spectroscopy have made possible to characterise the materials present. The minerals α-quartz, albite, microcline, muscovite, phlogopite, celadonite, beryl and anatase have been identified in the granitic rocks supporting the paintings, while dolomite and calcite are dominant in the calcareous rocky substrata. Haematite is the main component of the red pictographs, whereas amorphous carbon and manganese oxides/oxihydroxides have been used in the black ones. Calcite, gypsum and amorphous carbon have been detected as additional components of the paint in some cases. Contamination with modern tracing materials (polystyrene and ε-copper-phthalocyanine blue) has been detected in several cases. The presence of pigments as decorative elements in megalithic monuments of Western France and its possible relation with those of the Iberian Peninsula create interesting expectations for the knowledge of the European megalithic culture

Section: Resultsmentioning

confidence: 80%

Raman microscopy of prehistoric paintings in French megalithic monuments

Hernanz

Iriarte

Bueno‐Ramírez

et al. 2015

“…Moreover, these compounds have been used in various applications, for example, in art works as pigments for pottery, mural paintings, and stained glass. Therefore, their proper characterization might provide an important tool in cultural heritage studies, or when addressing the degradation of art works due to the weathering …”

Section: Introductionmentioning

confidence: 99%

Raman spectra of natural manganese oxides

Bernardini

Bellatreccia

Municchia

et al. 2019

138

182

Manganese oxides occur typically as cryptocrystalline and fine-grained mixtures of different Mn-phases, carbonates, silicates, and Fe oxides/hydroxides; thus their characterization by standard methods, such as X-ray diffraction, is extremely challenging. These materials have been widely used in various applications over the millennia, for example, in art works as pigments for pottery, mural paintings, stained glass, and recently, as nanostructured materials with very attractive physicochemical properties. Furthermore, they are important geomaterials that could play a key role in environmental applications, by controlling the partitioning of arsenic and heavy metals between rocks, soils, and aqueous systems. Raman spectroscopy, which is a punctual and nondestructive technique, has been widely used to characterize these materials. However, literature data are often conflicting and contradictory, usually not allowing a proper identification of the Mn species. In this work, we characterize the most common natural manganese oxides by combining X-ray powder diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy. Our data show that some manganese oxides have characteristic Raman spectra and can be easily recognized by using Raman spectroscopy alone, whereas integration of Raman data with other techniques is mandatory to characterize minerals that have almost identical Raman spectra. With this respect, Raman spectroscopy is the only technique allowing an easy discrimination between hollandite [Ba(Mn 4+ 6 ,Mn 3+ 2 )O 16 ] and cryptomelane [K(Mn 4+ 7 ,Mn 3+ )O 16 ]. The final goal of this work is to provide reference Raman spectra, acquired on previously well-characterized Mn samples to facilitate the application of Raman spectroscopy in the study of these geomaterials.

“…Darchuk et al found red and yellow ochres in rock‐painting pigments from Egypt (Gilf Kebia area), and claimed also the presence of rutile. Jezequel et al investigated, using Raman, X‐ray diffraction, ICP/MS and analytical TEM, some paintings from the Magdalenian age in the Grottes de la Garenne (Saint‐Marcel, Indre, France) and objects found on the floor, which could have been used as ‘crayons’. Hematite, clays, carbon matter and carbonates were found in the red pigments and in some crayons.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of minerals and mineral pigments in archaeometry

Bersani

Lottici

2016

144

Minerals, as raw structural materials or pigments, play a fundamental role in archaeometry, for the understanding of nature, structure and status of an artefact or object of interest for cultural heritage. A detailed knowledge of the mineral phases is crucial to solve archaeological problems: Raman spectroscopy is a powerful investigation technique and has been applied extensively in the last 30 years on mineral identification and on pigment degradation. Here we report an updated review, covering the last decade, of the applications of Raman techniques to issues in which raw minerals, including mineral pigments, are involved. Particular attention is devoted to cases where the Raman analysis of minerals is deeper than a simple identification of the phases present in an archaeological or artistic object. Copyright © 2016 John Wiley & Sons, Ltd.