Younger Dryas Impacts

The Younger Dryas Impact Hypothesis (YDIH) is a scientific proposal based on numerous findings that the onset of the “Younger Dryas” (YD) period at the end of the last glacial era around 12,800 years ago was the result of a complex set of cosmic and oceanic events.^[1][2] YDIH is an additional explanation for the hypothesis that YD was caused by “shutdown” of ocean currents, such as the “North Atlantic Conveyor”, due to a sudden influx of freshwater from rapid glacial melt.^[3] “The prevailing hypothesis is that the cooling and stratification of the North Atlantic Ocean were a consequence of massive ice sheet discharge of meltwater and icebergs and resulted in reduction or cessation of the North Atlantic Conveyor.”^[4][5]

From the start, it has been speculated, and to some extent proven, that a meteor air burst, caused by a comet hitting the atmosphere over North America, created what we call the Younger Dryas Impact(s). It has been proposed that the event or events triggered extensive burning across the landscape, an impact winter that destabilized the Atlantic Conveyor, which then triggered abrupt climate change, which then contributed to mass extinctions. YDIH “proposes that the airburst or impact of a comet ~12,850 years ago caused the ensuing ~1200-year-long Younger Dryas (YD) cool period and contributed to the extinction of the Pleistocene megafauna in the Western Hemisphere and the disappearance of the Clovis PaleoIndian Culture.”^[6] YDIH “posits that fragments of a large, disintegrating asteroid/comet struck North America, South America, Europe, and western Asia ~12,800 years ago. Multiple airbursts/impacts produced the YD boundary layer (YDB), depositing peak concentrations of platinum, high-temperature spherules, meltglass, and nanodiamonds, forming an isochronous datum at >50 sites across ~50 million km(2) of Earth's surface. This proposed event triggered extensive biomass burning, brief impact winter, YD climate change, and contributed to extinctions of late Pleistocene megafauna.”^[7]

These proposals, though reasonable, and based in evidence, spark amazing backlash in counter-claims, dithering critiques, and personal attacks. Starting in 2022, researcher Graham Hancock presented a Netflix series, “Ancient Apocalypse”, which specifically covered some of the evidence of YDIH and its backlash, including the personal attacks on Hancock himself. YDIH has most certainly become a lightning rod issue among scientists and academics, sparking heated battles among reactionaries online, all of it reaching a fever pitch after Ancient Apocalypse aired. The Pseudopedia page for YDIH has captured much of the debate in a disturbing, though typical, mess of calumny, opinions, and fallacies. Their lopsided and negative page certainly does not provide a “neutral point of view” on YDIH, and it is almost unreadable (note, this article has been adapted from it, with corrections and omissions).

A Brief History of Younger Dryas

As early as 1883, the basic idea that a comet struck North America at the end of the last ice age was first proposed by the American congressman Ignatius Donnelly, who suggested it formed the Great Lakes and caused a sudden extreme cold period, which devastated animal and human populations.

2000s

Over a century later in 2001, Richard Firestone and William Topping published their first version of YDIH, “Terrestrial Evidence of a Nuclear Catastrophe in Paleoindian Times” in Mammoth Trumpet, a newsletter of the Center for the Study of the First Americans.^[8] They proposed that “the entire Great Lakes region (and beyond) was subjected to a particle bombardment and a catastrophic nuclear radiation...” This cataclysm generated a shock wave which gouged out the Carolina Bays and reset the radiocarbon clock. Carolina Bays are relic geomorphological features developed from eolian and lacustrine processes. Multiple lines of evidence, including radiocarbon dating, optically stimulated luminescence dating, and palynology, indicate that the Carolina Bays predate the start of the Holocene Period. Fossil pollen recovered from cores of undisturbed sediment taken from various Carolina Bays in North Carolina by Frey^[9][10] Watts,^[11] and Whitehead^[12][13] document the presence of full glacial pollen zones within the sediments filling some of the bays. The range of dates can be interpreted that the bays were either created episodically over the last tens of thousands of years or were created at time over a hundred thousand years ago and have since been episodically modified.^{[14][15][16][17]}

The Cycle of Cosmic Catastrophes: How a Stone-Age Comet Changed the Course of World Culture, by Richard Firestone, Allen West and Simon Warwick-Smith, was published in 2006. The authors proposed that a large meteor air burst or impact event of one or more comets initiated the Younger Dryas cold period about 12,900 years ago^[18] In May 2007, at a meeting of the American Geophysical Union in Acapulco, Firestone, West, and around twenty other scientists made their first formal presentation of the Youger Dryas Impact Hypothesis.^[19] Later that year, the group published a paper in the “Proceedings of the National Academy of Sciences”, suggesting the impact event may have led to an immediate decline in human populations in North America.

C. Vance Haynes Jr. published data in 2008 to support the synchronous nature of “black mats” of char buildup, emphasizing that independent analysis of other Clovis sites was required to better support the hypothesis. He was skeptical of the impact as the cause of the Younger Dryas and the associated megafauna extinction, but concluded ”...something major happened...that we have yet to understand.”^[20] The first debate between proponents and skeptics was held at the 2008 Pecos Conference in Flagstaff, Arizona.^[21][22] In 2009, papers by Kerr^[23] and Kennett^[24] in the journal 'Science'' asserted that nanodiamonds were evidence for a swarm of carbonaceous chondrites (or comet fragments) from air burst(s) or impact(s) which set parts of North America on fire, caused the extinction of most of the megafauna in North America, and led to the demise of the Clovis culture. A special debate-style session was convened at the 2009 AGU Fall Meeting in which skeptics and supporters alternated in giving presentations.^[25][26]

2010s

Astronomer William Napier published a model in 2010 suggesting that fragments of a comet, initially 50 to 100 kilometers in diameter, could have been responsible for such an impact, and the Taurid Complex was formed from remaining debris. In 2012, a paper by Bunch and others reported the discovery of scoria like objects (SLO) and stated they were consistent with an impact or airburst.^[27] In 2013, Petaev and others reported a hundredfold spike in the concentration of platinum in Greenland ice cores roughly dated to 12,890 years ago.^[28] This anomaly was attributed to a small local iron meteorite fall without any widespread consequences.^[29]

In 2017, C R Moore and others reported a platinum anomaly at eleven continental sites dated to the Younger Dryas, which is linked with the Greenland Platinum anomaly.^[30] While in 2018, “extraordinary biomass-burning episodes” associated with the Younger Dryast were reported by Wolbach and others^[31][32] and Lynch.^[33] In 2019, Pino and others reported evidence in sediment layers with charcoal and pollen assemblages both indicating major disturbances at Pilauco Bajo, Chile in sediments dated to 12,800 BP. This included rare metallic spherules, melted glass, and nanodiamonds thought to have been produced during airbursts or meteorite impact. Pilauco Bajo is the southernmost site where evidence of the Younger Dryas impacts has been reported. This has been interpreted as evidence that a strewn field from the Younger Dryas impact event may have affected at least 30% of Earth's radius. Also in 2019, CR Moore and others reported analysis of age-dated sediments from a long-lived pond in South Carolina showed not just an overabundance of platinum but a platinum/palladium ratio inconsistent with a terrestrial origin, as well as an overabundance of soot and a decrease in fungal spores associated with the dung of large herbivores, suggesting large-scale regional wildfires and at least a local decrease in ice age megafauna.^[34]

Thackery and others reported in 2019 that a ~10 ppb platinum enrichment in peat deposits at Wonderkrater in South Africa was associated with the YDB.^[35] Research that year at White Pond near Elgin, South Carolina, conducted by CR Moore from the University of South Carolina and 16 colleagues, used a core to extract sediment samples from underneath the pond. The samples, dated by radiocarbon to the beginning of the Younger Dryas, were found to contain a large platinum anomaly, consistent with findings from other sites. A large soot anomaly was also found in cores from the site.^[36][37]

2020s

In 2020, a group led by Allen West reported high concentrations of iridium, platinum, nickel, and cobalt at the Younger Dryas boundary in material from Tell Abu Hureyra. They concluded that the evidence supports the impact hypothesis,^[38][39]. In 2022, a paper by geologist James L. Powell claimed that opponents of YDIH had prematurely rejected the theory^[40], arguing that many independent studies have reproduced evidence at dozens of YD sites.

In a December 2023 article by CR Moore and others^[41] stated that “anomalous peak abundances of platinum and Fe-rich microspherules with high-temperature minerals have previously been demonstrated to be a chronostratigraphic marker for the lower Younger Dryas Boundary (YDB) dating to 12.8 ka,” was found in sediments at Wakulla Springs, Florida. “The study confirms the utility of this YDB datum layer for intersequence correlation and for assessing relative ages of Paleoamerican artifacts, including those of likely Clovis, pre-Clovis, and post-Clovis age and their possible responses to environmental changes known to have occurred during the Younger Dryas cool climatic episode.”

A Philosophical Conclusion

Of course, all evidence cited above (which is only a portion of the total) has had vehement opposition in counter-claims and critical research. Most of it falls into the category of fallacious attack, by presupposing one researcher's materials dating is irrefutable while itself magically refuting all of the materials dating evidence supporting the theory. Some of it suffers from an inability to “see the forest for the trees”, because ultimately, the Younger Dryas Imact Hypothesis/Theory is a plausible scenario to capture the majority of world-wide findings in Geology, Archaeology, and Astronomy related to the period.

The attacks on YDIH and its proponents come off as simply mean-spirited desperation due to the fact that YDIH threatens many academic sacred cow pet theories (and funding). Such is common in academic Science, which takes time to work its way around to accepting some theories. We may never know for sure what exactly happened 12,800 years ago, but the fact that we do not currently know it all does not itself support the wild counter-theories and personal attacks made. What we do know is that our Earth is impacted by meteors and comet debris relatively constantly in geological time, and some have been catastrophic. We also know that impact craters dot the planet and Moon, and that meteor airbursts yield tremendous destructive energy. Consider the impact of a significant crater or airburst on today's populations and technology. Would all of this suddenly get real then?

To suppose the entirety of YDIH is somehow invalidated because one or two potentially irrelevant pieces of evidence may not fit based on a different type of materials dating, for example, while the critic also claims YDIH is “pseudoscience”... Well, that is itself pseudoscience. We should be careful of “experts” online who denounce a hypothesis which has significant evidence. There are many areas in Science with far less evidence than YDIH, yet they are considered sacrosanct - some even have zero evidence. Among these are String Theory, Dark Energy, Time/Spacetime, and others...but those are topics for different pages...

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