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.
last week two intriguing possibilities: the famous cave paintings in France and Spain may be as much as 15,000 years older than previously established; Neanderthals may have been cave painters as well as were the anatomically modern humans who replaced them.
A team led by Alistair Pike of the University of Bristol in the United Kingdom sought to confirm previously assigned dates or establish new dates for cave paintings by applying uranium series analysis of calcium carbonate deposits overlaying or underlaying paints applied to cave walls.
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.
But the antiquity of the cave paintings in Spain means that Pike and his colleagues can’t dismiss the possibility that Neandertals created the ancient works of art, since they were also living in the region when arrived.
The researchers dated calcite deposits associated with 50 paintings in 11 different caves.
The caves investigated by Pike and his team contain no organic material and thus cannot be dated by carbon-14.
U-series dating of the calcium carbonate layers in the Spanish caves investigated by Pike is the only viable method at present.
The answer, in the minds of evolutionary anthropologists, depends on the dates for when Neanderthals and early modern humans lived, and dates newly assigned to the paintings. Alistair Pike and colleagues report they have uranium-series-dated cave paintings in 11 caves in northern Spain and discovered the oldest known cave art in Europe.
Their report follows close on the heels of an announcement that artwork in southern Spain is suspected of being equally ancient.
Researchers have shown that some cave paintings in northwestern Spain are older than expected, which raises some questions about the artists responsible.