Chemical and mineralogical characteristics of the pigments of archaeological rupestrian paintings from the Salão dos Índios site, in Piauí, Brazil
| Autor: | Maria Conceição Soares Meneses Lage, Luis Carlos Duarte Cavalcante, Laiane de Moura Fontes, Fabiana Matos de Oliveira, Lívia Martins dos Santos, Heralda Kelis Sousa Bezerra da Silva, José Domingos Fabris, Benedito Batista Farias Filho |
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| Rok vydání: | 2018 |
| Předmět: |
Archeology
Goethite Materials science 010401 analytical chemistry Iron oxide Hematite 010403 inorganic & nuclear chemistry 01 natural sciences Archaeology 0104 chemical sciences chemistry.chemical_compound Pigment chemistry visual_art Mössbauer spectroscopy visual_art.visual_art_medium Small particles Fourier transform infrared spectroscopy |
| Zdroj: | Journal of Archaeological Science: Reports. 18:792-797 |
| ISSN: | 2352-409X |
| DOI: | 10.1016/j.jasrep.2018.01.035 |
| Popis: | The archaeological site Salao dos Indios is located in the municipality of Castelo do Piaui, Brazil. The site is geographically part of a larger concentration of several archaeological sites of similar rupestrian graphical characteristics, including non-figurative paintings represented in a variety of colors. The work essentially devoted to identifying the mineralogical features of the pigments from this Salao dos Indios archaeological site is reported, basing on results from microscopic examinations and from physical and chemical analyses by electronically- and X ray-induced energy dispersive spectroscopies, Fourier transform infrared spectroscopy, powder X-ray diffraction and 57Fe Mossbauer spectroscopy. The way by which the prehistorical painting pigments were prepared and applied over the rock wall was auxiliary investigated by examining samples under binocular lenses. Results reveal that the pigments were primarily prepared in the liquid or paste form, using iron-rich clayey materials. The Mossbauer data obtained for three samples of reddish rupestrian paintings showed that the dominant iron oxide in the pigment is hematite (αFe2O3). The range of red hues of these rupestrian paintings can be explained by the different proportions of hematite that make up the layers of these prehistoric paints, with different mean particle sizes, reflecting fractions of particles undergoing different degrees of collective magnetic excitations as it can be drawn from the Mossbauer subspectra. Other iron-bearing species rendering spectral doublets were also observed, certainly due to superparamagnetic iron (oxyhydr)oxides (likely including some goethite) in very small particles or paramagnetic iron in the crystalline structure of phyllosilicates. |
| Databáze: | OpenAIRE |
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