Find paints picture of human history

A hundred thousand years ago, not long after Homo sapiens emerged as a species, a craftsman -- or woman -- sat in a cave overlooking the Indian Ocean, crushed a soft rusty red rock, mixed it inside a shell with charcoal and animal marrow, and dabbed it on something -- maybe a face, maybe a wall.

Before the person left, he or she stacked the shell and grindstones in a neat pile, where they lay undisturbed for a hundred millennia.

Unearthed in 2008 and described Friday in the journal Science, these paint "toolkits," researchers say, push deeper into human history evidence for artistic impulses and complex, planned behavior.

"They probably understood basic chemistry," said Christopher Henshilwood, the archaeologist who led the discovery team.

Traces of paint on the tools show that the cave-dwellers mixed ochre -- red or yellow minerals that contain metal oxides -- with marrow from bones, charcoal, flecks of quartz, and a liquid, likely water. Paint experts at the Louvre in Paris performed the analysis.

With ground ochre as the base, the marrow and charcoal acted as binders. The quartz could have made the compound sticky, while water -- in the right amount -- provided the proper consistency.

This deliberate mixture "implies that people at the time had complex cognition," said Lyn Wadley, an archaeologist at the University of Witswatersrand in Johannesburg. Wadley studies early ochre paint but was not involved in the research. "They could multitask and think in abstract terms."

The cave, called Blombos, sits in a cliff on the coast of South Africa about 180 miles east of Cape Town. It shows signs of human use starting 130,000 years ago. Protected from wind and rain and close to seafood, antelope and other game, the cave apparently made for an inviting stopover for wave after wave of nomadic hunter-gatherers.

Henshilwood, who splits his time between the University of Bergen in Norway and the University of Witswatersrand, began excavating Blombos in 1992, digging through layers of animal bones, crustacean shells and other evidence of occupation during the Paleolithic, or Stone Age. But the deepest layer, which the team reached in 2008, was different. Instead of scattered remains, two tidy paint "toolkits" emerged, covered by sand. Both included fist-sized abalone shells and lay in neat piles.