July 24, 2012

Volcanic ash didn't kill Neandertals, modern humans did

Related story by Michael Balter:
The team collected samples containing CI cryptotephra from four central European caves where stone tools and other artifacts typical of Neandertals and modern humans have been found. They also gathered the particles from a modern human site in Libya and from marshland and marine sites in Greece and the Aegean Sea. The results, the team argues in a paper published online this week in the Proceedings of the National Academy of Sciences, are incompatible with the hypothesis that the CI was responsible for Neandertal extinction, at least in central Europe. The CI cryptotephra lie above, and so postdate, the transition from Neandertal to modern human stone tool types at all four central European sites, indicating that modern humans had replaced Neandertals before the catastrophic events of 40,000 years ago.
It's a little strange that modern humans arrive in Europe by the late 40,000s cal BP, replace the Neandertals, and shortly -in geological terms- thereafter, a massive volcano goes off on them. Perhaps, a little nemesis?

PNAS doi: 10.1073/pnas.1204579109

Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards

John Lowe et al.

Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters.


1 comment:

eurologist said...

It's good to have independent confirmation and dating of a 40,000 year-old layer that at least roughly agrees with the very difficult modern carbon dating procedures for that age (and that some have criticized as unreliable).