Chilean researchers documented over 150 rock art paintings in the Coquimbo Region, South of Atacama Desert in northern Chile. Specialised digital analysis software was used to detect colours and patterns unobservable in normal conditions by human eye.
The researchers have taken photos of the rock art on an area covering 115 square kilometres, created by hunter-gatherers between 2000 BC and 500 AD, and analysed them with use of DStretch software, applying algorithms predefined for working with rock art. The newly discovered paintings consist mainly of lines, circles and squares of different colours. The pigments used were possible derived from locally available minerals (red with hematite, green with copper, yellow with geothite, black with coal), probably combined with animal fat. The artists may have used brushes, fingers or a combination of both to create the images. The images that were created with black pigment, derived from coal were suitable for radiocarbon analysis, allowing for more accurate dating.
The research suggests that the paintings were created by different groups of pre-Hispanic inhabitants of the Limari area. It is possible, that the rock art was used to mark the boundaries of territories of people from the coastal area and others from the mountains. Images created by both groups have similarities such as the absence of animal and human figures. There are also differences in design composition (more parallel lines in the coastal area than in the mountains) and use of colours (wider variety of colours in the mountains).
(after Scientific American)