Multi-Analytical Characterization of Rupestrian Precolonial Paintings of Inhuma, Piauí, Brazil

The chemical-mineralogical characterization of rupestrian paintings in red, white, black and yellow colors, which decorate the rocky walls from the archaeological sites of Ema and Furna dos Índios (Inhuma, Piauí, Brazil) was performed. The chemical analyses were performed in situ by the non-invasive analytical technique X-ray fluorescence spectrometry (XRF) as well as in laboratory using a non-destructive approach, without previous sample preparation, and Raman microscopy, and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) techniques. The results, when together, allowed unequivocal identification of the main substances responsible for the color pigments, namely, hematite (red pigment), gypsum (white pigment), amorphous carbon from charcoal (black pigment) and goethite (yellow pigment).

针对巴西皮奥伊州因胡马市埃马（Ema）遗址与印第安洞窟（Furna dos Índios）岩壁上的红、白、黑、黄四色岩画，本研究完成了化学-矿物学表征工作。化学分析分别采用两种方式开展：现场使用非侵入式分析技术X射线荧光光谱法（X-ray fluorescence spectrometry, XRF）；实验室层面则采用无需样品预处理的无损检测方案，结合拉曼显微镜、扫描电子显微镜-能量色散X射线光谱联用（scanning electron microscopy coupled with energy dispersive spectroscopy, SEM-EDS）技术。综合所有分析结果，可明确鉴定出各色彩颜料的主要成分：红色颜料为赤铁矿（hematite），白色颜料为石膏（gypsum），黑色颜料为木炭来源的无定形碳，黄色颜料为针铁矿（goethite）。