Article by Ferris Jabr, via New York Times Magazine

Three years ago, on an expedition to Sulawesi, one of the larger islands in the Indonesia archipelago, the archaeologist Adam Brumm visited a cave decorated with ancient art: mulberry-colored hand stencils and paintings of corpulent pig-deer and midget buffalo, complete with hairlike brush strokes. Squeezing past a giant block of limestone at the cave’s entrance, Brumm made his way toward a narrow nook and crawled along it. There, on a section of ceiling less than a foot above his head, he saw ghostly silhouettes of human hands speckled with warty growths of calcite known as “cave popcorn.”

A year later, Brumm returned with his colleague Maxime Aubert and a diamond-bladed saw. Aubert specializes in using calcite — which contains trace amounts of steadily decaying radioactive uranium — to determine precise dates for ancient rock art. Researchers had long assumed that Sulawesi’s cave paintings were less than 10,000 years old; anything older, the thinking went, would have eroded in the island’s humid climate. But Brumm and Aubert’s analysis, published in October, revealed that one hand stencil is at least 39,900 years old — the oldest hand stencil on record. A nearby painting of a female pig-deer was estimated to be 35,400 years old, making it one of the most ancient examples of figurative art.

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