Professor Pettigrew and his colleagues studied 80 of these Bradshaw rock artworks – named for the 19th-Century naturalist who first identified them – in 16 locations within Western Australia’s Kimberley region.
They concentrated on two of the oldest known styles of Bradshaw art – Tassel and Sash – and found that a vast majority of them showed signs of life, but no paint.
The team dubbed the phenomenon “Living pigments”.
via BBC News – Ancient rock art’s colours come from microbes.