And you thought the Mona Lisa was old.
Researchers say they've found the earliest known drawing on a stone fragment in South Africa. The simple cross-hatched pattern dates back 73,000 years to the Middle Stone Age, which makes it some 30,000 years older than the oldest known abstract drawings.
The drawing, found in a cave 186 miles (300 kilometers) east of Cape Town, was engraved with red ochre pigment. The stone canvas measures just 1.6 inches (4 centimeters) and is thought to have once been part of a larger grindstone, meaning we're probably seeing only part of the original design.
Archaeologists have been excavating the Blombos Cave since 1991 and found bone awls, spear points, beads made from shells and ochre engraved with geometric patterns.
The 73,000-year-old silcrete flake, which currently bears the not-too-highfaluting title L13, was excavated in 2011. But it was only on Wednesday that a team of international researchers, led by Christopher Henshilwood of Norway's University of Bergen, shared their findings on the rock. Their research appears in the journal Nature.
The team studied the nine red lines on the flake using techniques involving advanced microscopes and lasers. They concluded the markings weren't natural, but had intentionally been applied to the stone.
"This demonstrates that early Homo sapiens in the southern Cape used different techniques to produce similar signs on different media," Henshilwood said in a statement. "This ... supports the hypothesis that these signs were symbolic in nature and represented an inherent aspect of the behaviorally modern world of these African Homo sapiens, the ancestors of all of us today."
In this case, the scientists say the techniques involved single strokes of a pointed ochrewith a tip between 1 and 3 millimeters thick (among its 2011 findings, the team also recovered snail shells containing residue of an ochre-rich paint). Our ancestors also used rubbing motions to decorate the stone, the scientists say.
But what does the drawing represent? It's fair to consider this a Rorschach test of sorts. Some people might look at it and see crossed spears or tangled branches. Others might see an ancient hashtag.
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