Pesky Details

4 Oct 2020

At https://phys.org/news/2020-09-modern-humans-westernmost-europe-years.html ... modern humans, in a new study, are said to have arrived in the westernmost parts of Europe between 41,000 and 38,000 years ago, some 5000 years earlier than previously allowed. Stone tools normally associated with modern humans, in this instance the Aurignacians, have been found in Portugal. This implies there was a rapid dispersal from the Eurasian, or Russian Plain. At the same time, we are informed excitedly, that modern humans probably occupied Europe prior to the extinction of the Neanderthals. This is of course theory based on the basis that modern Europeans, living today, preserve a small amount of Neanderthal DNA and must have mated with them. Presumably the article was written prior to the discovery that Neanderthal Y chromosomes are no different to those of modern humans. If any mating took place it is likely to have occurred thousands of years prior to 4,000 years ago. On top of that we have Bayesian methodology. Thjis has allowed C14 dating to move back to around 45,000 years ago - which basically means that what is now dated to 41,000 years ago would previously have been dated somewhat younger. A couple of thousand years for example. It also ignores the fact that earlier discoveries were not dated by Bayesian methodology and if their dates are not modified, as in the case of the study dates, and then it would appear that Neanderthals overlapped with modern humans. Not only that, the modern humans, evien in this study, are known solely by their tool repertoire. Not by skeletal material found in the cave, Lapa do Picareiro.

It is all very well leap frogging older C14 dates but what does the archaeology tell us. To understand the situation it is worth taking a look at an article in Quaternary Science Review 29 (2010) pages 3881-3893. The article concerns the Laschamps geomagnetic reversal at or around 40,000 years ago. It wonders if the disappearance of the Neanderthals might have a connection with a weak magnetic field, detrimental cosmic rays, and a huge ozone hole through which leached dangerous radiation. They make the point there is no evidence that Neanderthals and modern humans co-existed. It is merely assumed so as the latter have genes of the former. Most of all, there is no interstratification of Neanderthal and Aurignacian remains in layers, or sediments found on cave floors. Neanderthal remains are always below those of modern humans. However, there is a caveat there as it is only at a few sites that Neanderthal occupation was followed by modern humans. There are plenty of sites with Neanderthal remains without an overtopping of modern human strata. As such, this gives hope for those eager to suggest mating rather than direct descent, modern humans the survivors of a catastrophic event. Even in the new study we are told that the stone tools of modern humans are in a layer above those of Neanderthals.

At https://phys.org/news/2020-09-ancient-dna-revealing-genetic-linkages.html ... ancient DNA reveals the genetic landscape of modern humans in East Asia. Here we have one of the first modern humans in what is now China, the equivalent of the Aurignacians, living in China from 40,000 years ago, at the same point in time as Europe. Tianyuan Man, found near Beijing, is regarded as the first modern human in what is now China. However, prior to the end of the Pleistocene there is evidence of varied DNA across China, until the Holocene