Thursday, December 23, 2010

[Geology2] Did volcanoes wipe out Neanderthals?

I hate when that happens . . .

http://www.world-science.net/othernews/101001_neanderthals

Did volcanoes wipe out Neanderthals?
Oct. 1, 2010
Courtesy of Current Anthropology
and World Science staff

Climate change following huge volcanic eruptions may have driven the
Neanderthal people to extinction and cleared the way for modern humans
to thrive in Eurasia, some scientists say, Researchers with the ANO
Laboratory of Prehistory in St. Petersburg, Russia, propose the idea in
a research paper the October issue of the journal Current Anthropology,
but stress that more data is needed. "[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," wrote the scientists,
Liubov Vitaliena Golovanova and Vladimir Borisovich Doronichev.

Neanderthals were a robust breed of early human relatives, which died
out after anatomically modern humans moved into Europe and Asia around
40,000 years ago. Theories have implicated modern humans in the
Neanderthals' demise, but the issue remains unsettled. Evidence for
volcanic disaster comes from Mezmaiskaya cave in southern Russia's
Caucasus Mountains, Golovanova and Doronichev said, a site rich in
Neanderthal bones and artifacts. Recent excavations of the cave, they
explained, revealed two distinct layers of volcanic ash that coincide
with major eruptions around 40,000 years ago. Geological layers
containing the ashes also show signs of abrupt climate change, they
added, showing very low pollen levels, an indication of a dramatic shift
to a cooler and dryer climate. Further, the second eruption seems to
mark the end of Neanderthal presence at Mezmaiskaya. Many Neanderthal
bones, stone tools, and bones of prey animals have turned up in the
earth below the second ash deposit, but none above it. The ash layers
correspond to what is known as the Campanian Ignimbrite super-eruption
some 40,000 years ago in 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 "œvolcanic winter" as ash
clouds obscured the sun, possibly for years, killing off animals and
radically altering ecosystems.

Anthropologists have long puzzled over the disappearance of the
Neanderthals and the apparently concurrent rise of modern humans. Was
there some sort of advantage that helped early modern humans out-compete
their doomed cousins? The new research suggests the advantage may have
been simple location, according to the authors. "Early moderns initially
occupied the more southern parts of western Eurasia and Africa and thus
avoided much of the direct impact" of the blasts, they wrote. And
while advances in hunting and social structure clearly helped modern
humans as they moved north, they also "may have further benefited from
the Neanderthal population vacuum in Europe."

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