New research suggests volcanic ash clouds may have suddenly altered the climate across Europe and central Asia
By Summit Voice
SUMMIT COUNTY — A sudden regional climate shift about 40,000 years ago may have pushed Neanderthals off the evolutionary cliff, paving the way for the spread of modern humans.
Strong evidence for this new hypothesis was recently uncovered in the Mezmaiskaya cave an artifact-rich archeological site in the Caucasus Mountains of southern Russia. During recent excavations, Russian researchers found two distinct layers of ash coinciding with large-scale volcanic eruptions dating back to the Neanderthal era.
More study of the layers showed there may have been an abrupt and potentially devastating change in ecological conditions. Sediment samples showed greatly reduced concentrations of pollen compared to surrounding layers — suggesting a dramatic shift to a cooler and dryer climate with less vegetation.
Further, the second of the two eruptions seems to mark the end of Neanderthal presence at Mezmaiskaya. Numerous Neanderthal bones, stone tools, and the bones of prey animals have been found in the geological layers below the second ash deposit, but none are found above it.
The study was led by Liubov Vitaliena Golovanova and Vladimir Borisovich Doronichev of the ANO Laboratory of Prehistory in St. Petersburg, Russia, and was published in the October issue of Current Anthropology.
“[W]e offer the hypothesis that the Neanderthal demise occurred abruptly (on a geological time-scale) … after the most powerful volcanic activity in western Eurasia during the period of Neanderthal evolutionary history,” the researchers write. “[T]his catastrophe not only drastically destroyed the ecological niches of Neanderthal populations but also caused their mass physical depopulation.”
The ash layers correspond chronologically to what is known as the Campanian Ignimbrite super-eruption which occurred around 40,000 years ago in modern day Italy, and a smaller eruption thought to have occurred around the same time in the Caucasus Mountains. The researchers argue that these eruptions caused a “volcanic winter” as ash clouds obscured the sun’s rays, possibly for years.
The climatic shift devastated the region’s ecosystems, “possibly resulting in the mass death of hominids and prey animals and the severe alteration of foraging zones.”
Anthropologists have long puzzled over the disappearance of the Neanderthals and the apparently concurrent rise of modern humans, questioning whether early modern humans were somehow better adapted to survive.
The new research suggests that the simple answer might be geography.
“Early moderns initially occupied the more southern parts of western Eurasia and Africa and thus avoided much of the direct impact of the … eruptions,” the researchers write. And while advances in hunting techniques and social structure clearly aided the survival of modern humans as they moved north, they “may have further benefited from the Neanderthal population vacuum in Europe, allowing wider colonization and the establishment of strong source populations in northern Eurasia.”
While the researchers stress that more data from other areas in Eurasia are needed to fully test the volcanic hypothesis, they believe the Mezmaiskaya cave offers “important supporting evidence” for the idea of a volcanic extinction.