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Using plasma chemistry, carbon was extracted from charcoal paint samples collected from megalithic monuments in north-west Iberia. Nine accelerator mass spectrometric radiocarbon dates on these paints establish their age to be within 1000 14 C years of each other, centred at approximately 5000 BP. These radiocarbon ages for megalithic paintings fall within the proposed time period for north-west Iberian megalithic culture. Multiple layers of paint on some stones show that more than one painting episode occurred.
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Steelman et al. (2005) studied this question.
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