No abstract

The third painted panel of the Hoz de Vicente rock shelter (Minglanilla, Cuenca, Spain) contains a series of prehistoric pictographs which were studied by Raman microscopy. Scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDX) and petrographic polarised light microscopy were used as auxiliary techniques. The results obtained indicate that well-crystallised haematite (α-Fe 2 O 3 ) of grain size less than 1 µm was used as red pigment. However, amorphous carbon, probably vegetable charcoal or soot, was used as the black pigment. A patina of whewellite and weddellite covers the areas of the painting panel with pictographs. The microstratigraphic study of a schematic figure revealed that the layer of pigment is sandwiched between layers of these hydrated forms of calcium oxalate produced by the activity of fungi and lichens. These products have also been detected in the layer of pigment. These findings will enable obtaining limiting radiocarbon 14 C accelerator mass spectrometry (AMS) dates for the corresponding pictorial events. On the other hand, crystallisation of gypsum in the external layers of the panel is related to the deterioration observed in the flaking areas. Gypsum and clayish minerals appear as the main components of an ochre-coloured accretion covering several parts of the panel.

Significant paintings from the Tito Bustillo (Ribadesella, Asturias) and El Buxu (Cardes, Asturias) caves, renowned archaeological sites of the Cantabrian Palaeolithic cave art, were studied by micro-Raman spectroscopy. Auxiliary techniques like infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electronic microscopy combined with energy dispersive X-ray spectrometry were also applied. Haematite (a-Fe 2 O 3 ) of three granular sizes (<1, <10 and <30 mm) is the main red component of these paintings. Wüstite, amorphous carbon, and Mn are additional components of some pigments. Hydroxyapatite was also detected in one pictograph. Calcite, a-quartz and clay minerals are used as filler materials. Particles of anatase are present in some cases. No organic binders were detected. Considering the main components, granular size, and secondary phases with Ni and Mn in the pigments it is concluded that the ochre quarry in the Tito Bustillo cave was not used to make the pigments of the selected paintings. Two figures of this cave seem to have been painted with a similar pigment. A possible relationship between paintings of both caves is discussed.

No abstract