An international team of researchers claims to have dated mysterious cave art in Borneo—a southeast Asian island that is the third largest in the world—to as early as 40,000 years ago, placing the works among the oldest known figurative depictions in the world. That’s according to a study published in the journal Nature.
Figurative artworks are those which are not abstract designs and depict real things, such as animals, humans and other objects.
The team says that the findings lend support to the view that cave art—one of the most important innovations in human cultural history—was being practiced in Southeast Asia at the same time as Europe, contrary to scientists’ long-held views.
For more than two decades, researchers have known about caves in the remote and rugged mountains of East Kalimantan—an Indonesian province of Borneo—which contain prehistoric paintings, drawings, and other imagery, including thousands of depictions of human hands (stencils), animals, abstract signs and symbols and other motifs.
According to the team led by Maxime Aubert from Griffith’s University, the results of Uranium-series dating show these artworks are older than previously thought. This technique does not date the pigments used in the paintings themselves but instead examines a layer of calcium carbonate, also referred to as calcite, which forms over it, or was present before the work was made.
“Uranium is radioactive and with time it decays to make another element, thorium,” Aubert told Newsweek. “The rate of decay is precisely known. The key is that uranium is soluble in water, but thorium is not. So, when a calcite coating forms from rainwater on top of a painting, it initially contains uranium but no thorium. If we take a sample thousands of years later and measure the ratio of uranium versus thorium, we can calculate the age of the coating.”
“The calcite layer on top of the painting provides a minimum age for the art and the layer underneath provides a maximum age,” she said. “For uranium-series dating, we have to demonstrate that the coating is relatively pure, and that the calcite is a close system for uranium and thorium. We were able to meet these conditions.”
The oldest piece of art the team dated—a large painting of an unidentified animal, probably a species of wild cattle—was found to have a minimum age of 40,000 years old, making it the oldest known figurative artwork, according to Aubert.
In addition, stencil art in the caves was shown to be of a similar age. One of these works, for example, was shown to have a maximum age of around 52,000 years.
The research also uncovered a major change in style within this culture around 20,000 years ago, marking a transition from depicting the animal world to the human world at a time when the global ice age climate was at its most extreme.
“Who the ice age artists of Borneo were and what happened to them is a mystery,” Pindi Setiawan, an Indonesian archaeologist from the Bandung Institute of Technology and co-author of the study, said in a statement.
The research suggests that the picture of how cave art emerged is complex, casting new light on the long-held view that Europe was the center for its development. Even though Borneo is now an island, throughout most of the ice age it lay at the easternmost tip of the vast continental region of Eurasia—with Europe at the westernmost tip.
“I think we’re starting to see a pattern where cave art seems to have developed and evolved more or less at the same time and in a similar way at opposite sides of the world [Borneo and Europe],” Aubert said.