It’s Labor Day and that means the Tusk is back. I tend to slack off posting in the summer, which means we have some catching up to do.
Last month a little noted but fascinating journal article was published providing empirical, genetic evidence for a central claim of the Comet Research Group since 2007: A dramatic loss of life due to the rain of comet fragments ~12,874 years ago, late June.
The paper demonstrates that the YDI hypothesis is predictive of future findings, a central feature of a valid hypothesis. For instance, here are two references from Firestone et al. (2007) (co-authored by your correspondent) which proposed that the impact decimated humans unfortunate to be present for the trauma.
We propose that the YD event resulted from multiple ET airbursts along with surface impacts. We further suggest that the catastrophic effects of this ET event and associated biomass burning led to abrupt YD cooling, contributed to the late Pleistocene megafaunal extinction, promoted human cultural changes, and led to immediate decline in some post-Clovis human populations
From the conclusion:
Our primary aim is to present evidence supporting the YD impact event, a major ET collision over North America at 12.9 ka, which contributed to the YD cooling, the massive extinction of the North American fauna, and major adaptations and population declines among PaleoAmericans.
And here is an excellent 2012 paper inferring a population crash from the decline of Clovis spear points beginning at the YD: Evaluating the Effect of the Younger Dryas on Human Population Histories in the Southeastern United States
The Argentinian gene sleuths prove they are a class act simply by mentioning the controversial and widely suppressed YD impact hypothesis. The paper could have stood alone without the references, and silently affirmed the YDIH, but this courageous bunch makes the obvious connection.
Based on past examples, I suspect the YDI references troubled the reviewers, and those “peers” likely watered down the text with regard to the controversial impact. So many thanks to these scientists for sticking their necks out. Others are not so brave.
Here is the paper with notable references highlighted.
Human Y chromosome sequences from Q Haplogroup reveal a South American settlement pre-18,000 years ago and a profound genomic impact during the Younger Dryas
In order to have a more integrated view about the settlement of the Americas it is necessary to analyze the environmental changes that influenced the human populations of the time. The Younger Dryas (YD) was a major large-scale rapid climate change detected in the Northern Hemisphere about 12,900–11,600 cal BP [20, 21]. The Younger Dryas impact hypothesis at 12,800 cal BP has been associated with the abrupt YD climatic changes, large-scale megafauna’s extinction and decline and/or reorganization of human populations [22–24].