The basic questions about early European cave art—who made it and whether they developed artistic talent swiftly or slowly—were thought by many researchers to have been settled long ago: Modern humans made the paintings, crafting brilliant artworks almost as soon as they entered Europe from Africa. Now dating experts working in Spain, using a technique relatively new to archaeology, have pushed dates for the earliest cave art back some 4000 years to at least 41,000 years ago*, raising the possibility that the artists were Neandertals rather than modern humans. And a few researchers say that the study argues for the slow development of artistic skill over tens of thousands of years.
Figuring out the age of cave art is fraught with difficulties. Radiocarbon dating has long been the method of choice, but it is restricted to organic materials such as bone and charcoal. When such materials are lying on a cave floor near art on the cave wall, archaeologists have to make many assumptions before concluding that they are contemporary. Questions have even arisen in cases like the superb renditions of horses, rhinos, and other animals in France's Grotte Chauvet, the cave where researchers have directly radiocarbon dated artworks executed in charcoal to 37,000 years ago. Other archaeologists have argued that artists could have entered Chauvet much later and picked up charcoal that had been lying around for thousands of years.
Now in a paper published online today in Science, dating expert Alistair Pike of the University of Bristol in the United Kingdom and archaeologist Paul Pettitt of the University of Sheffield in the United Kingdom, together with colleagues in Spain, applied a technique called uranium-series (U-series) dating to artworks from 11 Spanish caves. U-series dating has been around since the 1950s and is often used to date caves, corals, and other proxies for climate and sea level changes. But it has been used only a few times before on cave art, including by Pike and Pettit, who used it to date the United Kingdom's oldest known cave art at Cresswell Crags in England.
U-series dating takes advantage of the fact that calcite, the form of calcium carbonate in stalactites and stalagmites, contains trace amounts of radioactive uranium-238, which decays to form atomic elements including radioactive thorium-230. By measuring the ratio of thorium-230 and uranium-238, daters can estimate how long ago the calcite was laid down.
Using a blade or an electric drill, the team took 50 small samples from calcite that directly overlay either paintings or engravings in 11 caves in northwest Spain. Because the calcite overlays the paintings, it must be younger than the art, and so yields minimum ages. In a few cases, the team also dated calcite underneath artworks, thus creating a "sandwich" that generated maximum and minimum dates.
The results, if correct, include the earliest ever reported date for cave art: A red disk from El Castillo Cave, on the Pas River in northern Spain, clocked in at a minimum of 40,800 years. The disk, part of a larger composition that includes dozens of other disks and some 40 stencils of human hands, could be older, depending on how soon after it was painted the calcite layer formed. Other early dates include 37,300 years for a hand stencil at Tito Bustillo Cave and 35,600 years for a club-shaped image at the famous Altamira Cave, whose artworks were previously thought to be only about 17,000 years old.
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