The Vulture Stone of Göbekli Tepe. Photo: Martin B. Sweatman and Dimitrios Tsikritsis

The stone carvings date from thousands of years ago, arranged in megalithic slabs of rock in circular enclosures.

They depict animals, including scorpions, birds, a frog, and a fox, among others. Since the Gobekli Tepe site in southern Turkey was discovered in 1963, the significance of the structures has remained an ancient mystery.

Now two researchers are putting forth their theory that the “Vulture Stone” at the center of the site is nothing less than a historical record of an apocalyptic comet event that ushered in a period of global cooling that completely changed life on Earth, they write in the journal Mediterranean Archaeology and Archaeometry.

The petroglyphs date from nearly 13,000 years ago and describe a “coherent catastrophism” event that brought on drastic global cooling.

Some of the symbols are ominous in their interpretation, conclude Martin Sweatman and Dimitrios Tsikritsis of the University of Edinburgh. A decapitated human is perhaps the most disturbing, they said.

“The pillar… provides the four zodiacal signs of an entire year in the correct temporal order,” they write. “This suggests an interpretation for the little headless man at the bottom; it is indicating probably the worst day ever in human history since the end of the ice age; the hypothetical Younger Dryas catastrophe.”

The arrival of comets that raised up huge ash clouds and a layer of darkness across the globe changed the world utterly, they hypothesize.

The Younger Dryas event was a cooling period for the northern hemisphere sometime between 13,000 and 11,500 years ago.

The scientists said the carved stone can be dated to 10,950 B.C., plus or minus 250 years, based on the arrangement of the animal constellations and the dating of the stone. (They used a computer model to determine the likelihood of whether the arrangement of figures could have been totally random, and found it was extremely unlikely). The Younger Dryas even they propose happened at roughly 10,890 B.C.

The evidence needs to be further studied – but the doomsday scenario seems plausible, they write.

“It seems prudent to betake coherent catastrophism seriously,” they conclude.