Proceedings of the National Academy of Sciences casts some doubt on the idea that the eruption of Italy's gigantic Campi Flegrei caldera volcano around 40,000 years ago killed off a significant portion Europe's resident neanderthal population when it buried much of Southern and Eastern Europe under silicate ash and plunged the planet into a renewed glaciation or "ice age" period. Doing so might have cleared the way for the entry of modern humans onto the continent. However, in the study that the new paper is based on, samples from four sites in the downwind area found that layers of previously un-examined microscopic glass particles from the eruption lie above the fossil record's transition from Homo neanderthalis to H. sapiens.
In other words, with these data points it looks like modern humans had already displaced the neanderthals prior to the massive eruption in downwind Eastern and Southern Europe. Unfortunately, the paper is not available in its entirety to the public at this time. That's a shame, because I'd happily read it in a heartbeat as I was under the impression that the displacement point between the two hominii species coincided with the eruption's visible ash layer in earlier excavations within the downwind region.
A medical doctor friend once told me that it's a common practice in the medical community to wait until three papers from three independent studies have verified a discovery before considering it a proven fact. While I'm somewhat attached to the idea that it was a smallish 'super volcano' eruption that provided the ecological disruption event which allowed Homo sapiens to displace the neanderthals, I'll file this dispute under undecided until more research has been published.
In other news
There were and always will be, eternally, migrations as there will always be births for life to continue. Migrations exist. Death does not exist!
-Milos Crnjanski, "Seobe"
On a related note, while looking for information related to the recent Proceedings article I came across an interesting article on paleogenetics that discusses the origins of modern European, North African, and Near East populations. Essentially it paints a picture them as a fusion of native populations with a rapidly expanding group that originated at the heart of the Fertile Crescent. The author's conclusion is that this was likely a kind of Guns, Germs, and Steel migration, in which agriculturalists armed with a package of technologies and food production methods spread outwards and absorbed the native nomadic hunter-foragers. This is a hypothesis that lines up well with recent archaeological digs in Eastern Europe I've read about elsewhere that show a westward spread of both agriculture and goods, as well evidence of holdout populations in remote, difficult to penetrate areas. Several of these mountainous and arboreal forest strongholds are also home to languages that predate the arrival of Indo-European descended languages, such as Hungarian, Finnish, and Basque.
If such is the case, it would be an interesting convergence of populations of genes and linguistic memes.