The Younger Dryas Impact Hypothesis (YDIH) is based on the claim that around 12,800 years ago the Earth had an encounter with a very large asteroid or comet that broke up in an airburst over North America and of which some fragments possibly hit the ground directly(a).
Many effects have been linked with this event with varying levels of enthusiasm including a suggested association with the demise of Atlantis. Elsewhere, megafaunal extinctions, cataclysmic floods, the disappearance of the Clovis people and the creation of the Carolina Bays(g), have all been proposed as consequences of this episode.
In 2006, Richard Firestone, Allen West & Simon Warwick-Smith published the foundations of the YDIH in The Cycle of Cosmic Catastrophes . A year later the hypothesis had a more public airing at the American Geophysical Union Press Conference, Acapulco, Mexico, on May 23(d). This was followed the same year by the publication of a formal paper in the Proceedings of the National Academy of Sciences of the United States of America(f).
Since then volumes have been written on the subject, both pro and con(c).
A 2014 paper(h) entitled Nanodiamond-Rich Layer Across Three Continents Consistent with Major Cosmic Impact at 12,800 Cal BP by Charles R. Kinzie et al., has developed further the idea of this event being associated with the Younger Dryas. In a similar vein is an article(f) from Megan Gannon.
December 2014 saw Graham Hancock raising the issue of a cometary cause for the Younger Dryas and its possible association with ancient Egypt(e).
Martin Sweatman brought further evidence to bear on this debate in an article(i) on the Graham Hancock website. This focuses on the investigations at Hall’s Cave in Texas described in a paper by Sun et al, where the team concluded that the trace elements found there could indicate a volcanic rather than an impact as the cause of the Younger Dryas cooling! Sweatman disagrees with their conclusions claiming that there seems to be an element of selectivity in choosing data, leading to a wrong conclusion.
2019 also gave us a paper that included an extensive bibliography and overview of the YDIH debate(k).
In 2020, the eminent geologist James Lawrence Powell published Deadly Voyager , which offered further support to the YDIH. This book was instrumental in changing the negative stance of a number of ardent sceptics including Michael Shermer(j).
In 2022 Powell concluded a paper reviewing the YDIH debates with the following
“Finally, we can now assess Sweatman’s suggestion that the YDIH may be ready for promotion from hypothesis to the status of theory. If we combine the definitions of “theory” from the National Academy of Sciences and the American Association for the Advancement of Science, it would read something like this:
‘A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence. One of the most useful properties of scientific theories is that they can be used to make predictions about natural events or phenomena that have not yet been observed.’
Those who have read this article and Sweatman’s have the information to decide whether the YDIH meets this definition. In this author’s opinion, there is a strong case that it does. Moreover, it should not be forgotten that no other single theory can explain the YD and its associated effects.”(l)
I note that Robert Schoch claims that there is no evidence to support the Younger Dryas impact theory, instead, he believes that “it was most likely due to reduced solar activity at that time, a solar shut-down.”(n) Schoch’s wide-ranging critique has been refuted by the Comet Research Group.(o)
In 2012, Jennifer Marlon et al published a paper, now made available by Marlon on the Academia website, in which they present “arguments and evidence against the hypothesis that a large impact or airburst caused a significant abrupt climate change, extinction event, and termination of the Clovis culture at 12.9 ka. It should be noted that there is not one single Younger Dryas (YD) impact hypothesis but several that conflict with one another regarding many significant details.”(m)
>Scienceopen.com is a website offering “A peer-reviewed open-access journal collection covering all aspects of airbursts and impacts on Earth by comets and asteroids”. October 2023 brought the publication of five papers on the subject(p).<
(k) YDIH: Younger Dryas Impact Hypothesis | Thongchai Thailand (tambonthongchai.com)
Richard Firestone together with his co-authors Allen West and Simon Warwick-Smith has written one of the most impressive accounts of a cosmic collision that led to the extinction in North America of large mammals such as the mammoth and sabre-toothed tiger and the concurrent disappearance of the Clovis people at the end of the last Ice Age.
Before what has become known as the Younger Dryas Impact Hypothesis (YDIH) was formulated, Firestone and William Topping speculated that North America was impacted by intense cosmic rays from a supernova in a 2001 paper entitled Terrestrial Evidence of a Nuclear Catastrophe in Paleoindian Times(l).
The YDIH also offers a credible explanation for the Carolina Bays. However, they propose that this collision had catastrophic global consequences. The three scientists are prepared to consider the possibility that Plato’s Atlantis story, however garbled, is related to the same episode[0110.328].
Since the publication of their book, some evidence(a)(k) has emerged that would appear to conflict with their core thesis. This criticism appears to be gaining support according to a May 2011 report(b)(d). However, in September 2012 it was reported that further intensive investigation has revealed flaws in the evidence gathering of Firestone’s critics(f). The interdisciplinary team of scientists from seven U.S. institutions concluded that “a disregard of three critical protocols, including sorting samples by size, explains why a group challenging the theory of a North American meteor-impact event some 12,900 years ago failed to find iron- and silica-rich magnetic particles in the sites they investigated.”
Strong resistance to the Firestone claims continued into 2013 when the Royal Holloway and the Sandia National Laboratories along with 13 other universities across the United States and Europe mounted further challenges(g).
The waters were muddied further when it was revealed that Allen West formerly known as Allen Whitt, who was convicted in California of posing as a state-licensed geologist(b) and fined $4,500! He legally changed his name in 2006. His respected co-authors were apparently unaware of his history and as a consequence of West’s central role in the data gathering, the hypothesis is considered by some to be tainted. This may be a case of shooting the messenger instead of the message, a view discussed at length on the Internet(e). A spirited defence of both West in particular and the theory of the team, in general, has also been written(c) and should be read in order to get a more balanced view of this particular controversy.
The core debate has rumbled on ever since. In July 2015 the University of California, Santa Barbara, released the results(h) of research, led by James Kennett, which again supported the impact theory and “has narrowed the date to a 100-year range, sometime between 12,835 and 12,735 years ago.”
The battle has continued, apparently inconclusively, with more papers being published by all sides. July 2018 saw an update of the controversy published on the Science News website(i), with no sign of the war ending.
Nevertheless, in late 2019, further evidence emerged that appears supportive of Firestone’s theory. Where previously nanodiamonds were an important feature in the presentation of his ideas the latest studies focus on platinum as an important marker(j).
2019 also gave us a paper that included an extensive bibliography and overview of the YDIH debate(m).
Inspiration resulting from an interview with Firestone led Kevin Curran to a study that ended with the publication of Fall of a Thousand Suns, in which he investigates the effect of extraterrestrial encounters on the development of early religious beliefs.
(m) YDIH: Younger Dryas Impact Hypothesis | Thongchai Thailand (tambonthongchai.com)