# The Younger Dryas impact hypothesis > About 12,900 years ago the Northern Hemisphere fell back into near-glacial cold for some 1,200 years. In 2007 a group of researchers proposed that a… Source: https://mysteriesdept.com/mysteries/younger-dryas-impact Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) Updated: 2026-10-27T17:48:33+00:00 --- **MYS** 0D51WZ1P63TH·Mystery · event # The Younger Dryas impact hypothesis **0** [Follow][Ask a question](https://mysteriesdept.com/questions/key-questions?mystery=younger-dryas-impact) The Younger Dryas impact hypothesis ![Group 1 SEM Images: High-temperature Fe-rich impact-related spherules.](https://mysteriesdept.com/media/folio/younger-dryas-impact-lead) Mario Pino et al. · CC BY 4.0 Claim Airbursts or impacts of a fragmented comet at the Younger Dryas onset caused the cooling, wildfires, megafaunal extinction and the end of Clovis⁠[[4]] First proposed October 2007 (Firestone and 25 co-authors, PNAS)⁠[[4]] Claimed date 12,835–12,735 cal BP (95%), from 354 dates at 23 sections⁠[[7]] Younger Dryas onset in Greenland 12,870 ± 30 years BP on the GICC05 timescale⁠[[2]] Crater of that age None known; Hiawatha (Greenland) dated to about 58 million years⁠[[28]] Mainstream view Rejected; summarised in a 2023 Earth-Science Reviews review by 13 authors⁠[[11]] Retractions Tall el-Hammam paper (Scientific Reports, April 2025); Baffin Bay and shocked-quartz papers (PLOS One, 11 February 2026)⁠[[23]] Status Partly explained Questions 0 of 7 answered People [**Allen West** Co-author of the 2007 paper and most later proponent papers](https://mysteriesdept.com/mysteries/younger-dryas-impact/people/FIG0D51X2780VPG/allen-west)[**James P. Kennett** Marine geologist, University of California, Santa Barbara; leading proponent](https://mysteriesdept.com/mysteries/younger-dryas-impact/people/FIG0D51X2F26W8W/james-p-kennett)[**Michail I. Petaev** Geochemist, Harvard; reported the GISP2 platinum anomaly](https://mysteriesdept.com/mysteries/younger-dryas-impact/people/FIG0D51X3P46ECE/michail-i-petaev)[**Richard B. Firestone** Nuclear chemist, Lawrence Berkeley National Laboratory; first author of the 2007 paper](https://mysteriesdept.com/mysteries/younger-dryas-impact/people/FIG0D51X1ZE3FWZ/richard-b-firestone)[**Christopher R. Moore** Geoarchaeologist, University of South Carolina; lead author of the retracted Baffin Bay paper](https://mysteriesdept.com/mysteries/younger-dryas-impact/people/FIG0D51X2PW5Y7G/christopher-r-moore) All 8 people › [**Mark Boslough** Airburst physicist; co-author of the refutation and PubPeer critic of the 2025 papers](https://mysteriesdept.com/mysteries/younger-dryas-impact/people/FIG0D51X3EA3SS8/mark-boslough)[**Todd A. Surovell** Archaeologist, University of Wyoming; led the 2009 replication](https://mysteriesdept.com/mysteries/younger-dryas-impact/people/FIG0D51X36G0YEB/todd-a-surovell)[**Vance T. Holliday** Geoarchaeologist, University of Arizona; lead author of the 2023 refutation](https://mysteriesdept.com/mysteries/younger-dryas-impact/people/FIG0D51X2YP15BV/vance-t-holliday) Catalog key**MYS** 0D51WZ1P63TH The Younger Dryas is the best-studied abrupt climate change on record. After the last ice age had begun to break up, temperatures over Greenland fell within decades back toward glacial values and stayed low for about 1,200 years before rising again just as abruptly⁠[[1]]. In Greenland ice the onset is dated to 12,870 ± 30 years before 1950⁠[[2]]. The usual explanation is a weakening of the Atlantic overturning circulation, of the kind that recurs through the last deglaciation⁠[[3]]. In 2007 Richard Firestone, Allen West, James Kennett and 23 co-authors proposed a different cause. At about 50 Clovis-age sites in North America they reported a thin layer at 12.9 ka with peaks in magnetic grains carrying iridium, magnetic microspherules, charcoal, soot, carbon spherules, nanodiamonds and fullerenes with extraterrestrial helium. They argued that one or more low-density bodies had exploded over northern North America, destabilised the ice sheet, started vast fires and contributed to the extinction of the megafauna and the end of the Clovis culture⁠[[4]]. The group, later organised as the Comet Research Group, has since reported the layer on four continents and added platinum, shocked quartz and meltglass to its proxies⁠[[5]]⁠[[6]]⁠[[7]]. The response has been a twenty-year test of reproducibility. Independent teams could not replicate the first results, found most proposed markers in sediments of other ages, and showed that only a few of the claimed sites are well dated to the onset⁠[[8]]⁠[[9]]⁠[[10]]. A 2023 review by thirteen geoscientists concluded that the hypothesis should be rejected⁠[[11]]; the proponents replied that the evidence has been corroborated many times⁠[[12]]. In February 2026 PLOS One retracted two of the group's 2025 papers, on Baffin Bay cores and on shocked quartz, after experts found problems with their age models, sampling and, in one case, the identification of the "cosmic" material⁠[[13]]⁠[[14]]. One strong signal remains unexplained: a platinum spike in Greenland ice close to the onset, whose source is still argued⁠[[15]]⁠[[2]]. Of the 7 questions on this site, 0 are answered. The most likely answer to “Did a catastrophe at about 12.8 ka cause the North American megafaunal extinctions and the end of Clovis?”, not yet confirmed: extinctions were driven by climate change and human hunting over a longer period; Clovis gave way to…. ### Key questionsset by the editors [**Did a catastrophe at about 12.8 ka cause the North American megafaunal extinctions and the end of Clovis?** ](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X9HM392H/did-a-catastrophe-at-about-12-8-ka-cause-the-north-american)Most likely: extinctions were driven by climate change and human hunting over a longer period; Clovis gave way to… [**Did an extraterrestrial impact or airburst occur at the onset of the Younger Dryas, about 12,800 years ago?** ](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X8AJ1304/did-an-extraterrestrial-impact-or-airburst-occur-at-the)Most likely: no impact or airburst occurred; the proposed markers are terrestrial or background cosmic material… [**What produced the platinum spike in the GISP2 ice core near the Younger Dryas onset?** ](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X92023AG/what-produced-the-platinum-spike-in-the-gisp2-ice-core-near)No answer ahead yet [**What triggered the Younger Dryas cooling?** ](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X99T2T4C/what-triggered-the-younger-dryas-cooling)Most likely: meltwater from the retreating ice sheets weakened the Atlantic overturning circulation [All 7 questions ](https://mysteriesdept.com/questions/key-questions?mystery=younger-dryas-impact) ## What happened The climate event is not in dispute. Oxygen-isotope and accumulation records from the GISP2 core at Summit, Greenland, show the Younger Dryas as a return to cold, dry, dusty conditions after the warm Bølling-Allerød, with the onset and the end each completed within decades⁠[[1]]. On the GICC05 timescale the onset falls at 12,870 ± 30 years BP⁠[[2]]. The Laacher See eruption in Germany, once proposed as a trigger, has been dated from buried trees to about 13,006 cal BP, some 130 years before the onset⁠[[16]]. [![The GISP2 ice core](https://mysteriesdept.com/files/7e0a0ed5029f2c47ba5f8f611847c1a8c23be93177a764d024a47ac0ed4659b5.png)](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XXAE2580/the-gisp2-ice-core) The GISP2 ice coreNOAA, 2013. Public domain[Artifact ](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XXAE2580/the-gisp2-ice-core) What is disputed is whether something else happened at the same moment. The impact hypothesis says that at the onset the Earth passed through the debris of a large fragmenting comet, whose airbursts and impacts deposited a thin boundary layer (the "YDB") across North America, Europe, the Middle East and beyond, burned a large fraction of the continents' vegetation, and caused an impact winter that tipped the climate⁠[[4]]⁠[[17]]. In this account the same event explains the extinction of mammoths, mastodons, horses and other North American megafauna and the end of the Clovis technology⁠[[4]]. **Map of the country** [Open the full map](https://mysteriesdept.com/mysteries/younger-dryas-impact/map) [Country][Continent] [+][−] 1 **Murray Springs, San Pedro Valley, Arizona** Archaeological site Within 1 km 2 **Blackwater Draw, near Clovis, New Mexico** Archaeological site Within 1 km 3 **Lubbock Lake Landmark, Texas** Archaeological site Within 1 km 4 **Arlington Canyon, Santa Rosa Island, California** Canyon Within 10 km 5 **Hall's Cave, Kerr County, Texas** Cave A region 6 **North America** Region A region Within 1 kmA regionNatural Earth ### Timeline **Timeline** Squeezed where little happened. Each mark is a published claim, by how it stands:AcceptedMost likelyStill possibleDisputedRuled out ## The accounts There are no witnesses; the accounts here are the published claims and the attempts to reproduce them. The founding paper reported the boundary layer at Clovis-age sites and Carolina Bays and listed seven kinds of marker⁠[[4]]. Later papers added nanodiamonds at 10 to 3,700 parts per billion⁠[[18]], about 700 analyses of spherules from 18 sites said to have melted above 2,200 °C⁠[[5]], platinum peaks at eleven North American sites⁠[[6]], ice-core and sediment evidence of a biomass-burning episode⁠[[17]], and meltglass at Abu Hureyra in Syria⁠[[19]]. [![Melt glass from Abu Hureyra](https://mysteriesdept.com/files/v/868025356f72b2062e2e28910d4e456b3512ea9f003e3dfedb83de4a6ebc2264/w800)](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XZRJ482C/melt-glass-from-abu-hureyra) Melt glass from Abu HureyraMoore et al. 2020, figure 2, 2020. CC BY-SA 4.0 (as tagged on Commons; the source figure is CC BY 4.0)[Artifact ](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XZRJ482C/melt-glass-from-abu-hureyra) The first independent test, at seven sites including two of the original ones, found none of the 2007 results⁠[[8]]. Electron microscopy of the claimed nanodiamonds identified graphene and graphene-oxide aggregates instead⁠[[20]]. A blind test at Lubbock Lake, Texas, in which two laboratories analysed identical splits of samples without knowing their depths, found microspherules and nanodiamonds low or absent at the boundary and abundant in one sample younger than 11,500 years⁠[[10]]. A chronological audit of the 29 claimed sites found only three securely within the proponents' own window for the onset⁠[[9]]. Reviews in 2011, 2014 and 2023 concluded that the evidence does not support an impact⁠[[21]]⁠[[22]]⁠[[11]]. The proponents' 2024 reply argues that dozens of studies, many by researchers outside the core group, have replicated the key evidence⁠[[12]]. The two retracted PLOS One papers show what the newest claims rested on. The Baffin Bay paper dated its layer by radiocarbon on foraminifera in 5 cm slices; the editors' experts found the dating inadequately reported, the calibration not done by the recommended method for that latitude and period (which gives younger ages, outside the Younger Dryas), material shown as cosmic spherule fragments to be foraminifera, sampling too sparse to establish background, and citations that did not support their statements⁠[[13]]. The shocked-quartz paper, on Murray Springs, Blackwater Draw and Arlington Canyon, built its age model from published dates but left some out, could not always say where dates came from, used dates spanning centuries, and did not sample the whole section, so spikes elsewhere and changes in sedimentation rate could not be excluded⁠[[14]]. Most authors disagreed with both retractions; the lead author of the Baffin Bay paper called the issue procedural, and a co-author acknowledged at least 43 incorrect references⁠[[23]]. They followed the April 2025 retraction of the group's 2021 paper claiming that an airburst destroyed the Bronze Age city of Tall el-Hammam, whose use of the Tunguska analogy and shock physics had been challenged in the same journal⁠[[24]]⁠[[25]]. ## What was recorded The physical record is of three kinds. First, sediment sections at archaeological and palaeontological sites, many with a dark organic "black mat" near the onset, in which the proposed markers were counted⁠[[4]]⁠[[22]]. Second, ice cores. In GISP2, Petaev and colleagues found a large platinum anomaly near the boundary with no matching iridium; the Pt/Ir ratio excludes mantle and chondritic sources, and the authors suggested an iridium-poor iron meteorite while noting such a body is unlikely to cause an airburst or wildfires⁠[[15]]. A 2025 study confirmed that the spike lasts about 14 years and lags the NGRIP sulphur spike by several decades, showed that the Laacher See tephra cannot be its source, and argued for fractionated volcanic gas from an Icelandic fissure eruption⁠[[2]]. Third, radiocarbon dates: the 354 dates the proponents modelled for the boundary⁠[[7]] and the large archaeological databases that record human activity through the period⁠[[26]]⁠[[27]]. [![The "black mat" at Murray Springs](https://mysteriesdept.com/files/v/6567fb0cf1698bf67a23a3b32e6145838c781afc6551a7c6564eab7f834e7636/w800)](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XYSA1G8Y/the-black-mat-at-murray-springs) The "black mat" at Murray SpringsAmmodramus (Wikimedia Commons), 2016. CC0[Artifact ](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XYSA1G8Y/the-black-mat-at-murray-springs) No crater has been tied to the event. The 31 km Hiawatha structure under the Greenland ice, at first suggested as a candidate, was dated in 2022 to 57.99 ± 0.54 million years⁠[[28]]. At Hall's Cave in Texas, osmium isotopes and siderophile elements across the boundary point to volcanic rather than extraterrestrial sources⁠[[29]]. ## The explanations The impact reading holds that a single cosmic event deposited a synchronous layer on four continents and drove the cooling, fires and extinctions⁠[[4]]⁠[[7]]. Its support is the number of sites and proxies reported and the Bayesian model placing the layer at 12,835–12,735 cal BP⁠[[7]]; its proponents count dozens of corroborating studies⁠[[12]]. Its difficulties are reproducibility, uniqueness and dating: independent and blind tests find the markers at other levels or not at all, most sites lack secure age control at the boundary, there is no crater, and no consistent physical scenario for the impactor has been set out⁠[[10]]⁠[[9]]⁠[[11]]. Two of the newest supporting papers have been withdrawn on exactly the dating and sampling grounds the critics had raised⁠[[14]]⁠[[13]]. The no-impact reading holds that the markers are ordinary: cosmic dust that falls continuously and is concentrated where sedimentation slows, spherules from volcanic and other terrestrial processes, charcoal from normal fire regimes, and misidentified carbon forms⁠[[21]]⁠[[20]]⁠[[11]]. In this reading the Younger Dryas is one of a series of deglacial cold events tied to the ocean circulation and needs no unique trigger⁠[[3]]. Its open problem is the Greenland platinum spike, which has no agreed source; the leading alternative is a volcanic eruption not yet identified⁠[[2]]. A narrower reading accepts the platinum spike as extraterrestrial but not the catastrophe: a differentiated, iridium-poor iron body could have left the signal without continental fires or a climate trigger⁠[[15]]. On the extinctions, the dates allow a short terminal-Pleistocene window but do not by themselves pick out a cause, and the archaeological record shows no population crash at 12.9 ka⁠[[30]]⁠[[22]]. ### Published claims **Published claims and their status** | Year | Who | Claimed | Status | Reason | |---|---|---|---|---| | 2007 | Richard Firestone, Allen West and colleagues⁠[4] | A comet impact or airburst over North America 12,900 years ago left a layer of impact markers, began the Younger Dryas cooling and contributed to the megafaunal extinctions. | Disputed | Independent tests have repeatedly failed to reproduce the markers or a synchronous layer, though proponents dispute the refutation⁠[11]⁠[12]. | | 2009 | Douglas Kennett, James Kennett and colleagues⁠[18] | Nanodiamonds occur in the boundary layer at several North American sites and are absent above and below it. | Disputed | A re-examination found the supposed nanodiamonds were misidentified graphene aggregates, and a blind test found no boundary peak⁠[20]⁠[10]. | | 2009 | Todd Surovell, Vance Holliday and colleagues⁠[8] | At seven sites, two of them sampled by Firestone's team, there are no peaks of magnetic grains or microspherules at the Younger Dryas boundary. | Accepted | A later blind test at Lubbock Lake also found no boundary peak⁠[10]. | | 2010 | Tyrone Daulton, Nicholas Pinter and Andrew Scott⁠[20] | There are no nanodiamonds in the Younger Dryas sediments; the reported ones are misidentified graphene and graphene oxide. | Accepted | The comprehensive 2023 review accepts the misidentification⁠[11]. | | 2010 | Wallace Broecker and colleagues⁠[3] | The Younger Dryas is one of several abrupt cold events of the deglaciation tied to the Atlantic overturning circulation and needs no unique trigger. | Accepted | The ocean-circulation reading remains the standard account of the cooling⁠[1]⁠[11]. | | 2013 | Michail Petaev and colleagues⁠[15] | A large platinum anomaly without iridium in Greenland ice at the Younger Dryas onset points to an unusual metal-rich source, perhaps an iron impactor. | Still possible | The spike is real, but a volcanic source has been proposed and Laacher See has been excluded as that source⁠[2]. | | 2013 | James Wittke and colleagues⁠[5] | About 10 million tonnes of impact spherules, melted above 2,200 °C, fell across four continents at the boundary. | Disputed | Critics find the proxies hard to identify and not unique to the boundary layer⁠[11]. | | 2014 | David Meltzer, Vance Holliday and colleagues⁠[9] | Only 3 of 29 sites claimed for the boundary layer have ages within the proponents' own window; the rest lack or misuse age control. | Accepted | The 2023 review finds that few high-proxy sites are well dated⁠[11]. | | 2015 | James Kennett and colleagues⁠[7] | A Bayesian model of 354 dates from 23 sections gives a boundary age of 12,835 to 12,735 years ago, consistent with a synchronous layer. | Disputed | Critics show many of the sections have weak or irrelevant age control, which the model inherits⁠[9]⁠[11]. | | 2016 | Vance Holliday, Todd Surovell and Eileen Johnson⁠[10] | In a blind test at Lubbock Lake, two laboratories found no peak of spherules or nanodiamonds at the boundary. | Accepted | The design removes the analysts' knowledge of depth, and no blind test has found the reverse⁠[11]. | | 2018 | Wendy Wolbach and colleagues⁠[17] | Ice-core and sediment markers show impact-set fires burned about a tenth of Earth's land and caused an impact winter. | Disputed | Geomorphic, stratigraphic and fire records show no catastrophic change at the boundary⁠[22]⁠[11]. | | 2020 | N. Sun and colleagues⁠[29] | The osmium and siderophile-element anomalies at Hall's Cave, Texas, are volcanic, not extraterrestrial. | Still possible | It fits the volcanic reading of the Greenland platinum spike, but the source eruption has not been identified⁠[2]. | | 2021 | Frederick Reinig and colleagues⁠[16] | The Laacher See eruption happened 13,006 ± 9 years ago, about 130 years before the Younger Dryas began in Greenland. | Accepted | The date comes from tree rings buried by the eruption and is used as a tie point between records⁠[16]. | | 2022 | Gavin Kenny and colleagues⁠[28] | Greenland's Hiawatha crater formed about 58 million years ago, not at the Younger Dryas onset. | Accepted | Two independent dating methods agree, which removes the one crater candidate proposed for the event⁠[11]. | | 2023 | Vance Holliday and twelve co-authors⁠[11] | No crater dates to the onset, the markers are misidentified or not confined to the boundary, the layer is not synchronous, and the hypothesis is refuted. | Accepted | Its points rest on published independent tests; the proponents' reply disputes the interpretation but brings no new data⁠[12]. | | 2024 | Martin Sweatman, James Powell and Allen West⁠[12] | Scores of papers corroborate the impact evidence, and differences of interpretation are not a refutation. | Disputed | It brings no new data, and two of the proponents' 2025 papers were retracted in 2026⁠[23]. | | 2025 | Christopher Moore and colleagues⁠[31] | Four Baffin Bay marine cores hold a 12,800-year-old layer with cometary dust, microspherules and a platinum anomaly. | Ruled out | The paper was retracted: recalibrated dates fall outside the Younger Dryas, and figured 'spherule fragments' were foraminifera⁠[13]. | | 2025 | James Kennett and colleagues⁠[32] | Shocked quartz at Murray Springs, Blackwater Draw and Arlington Canyon marks cosmic airbursts at the Younger Dryas onset. | Ruled out | The paper was retracted because its age model omitted available dates and the sections were not fully sampled⁠[14]. | | 2025 | Charlotte Green and colleagues⁠[2] | The Greenland platinum spike did not come from Laacher See and may record gases from an Icelandic fissure eruption. | Still possible | Laacher See is excluded by its own element data; the proposed Icelandic eruption has not been identified in other records⁠[2]. | | 2026 | PLOS One editors⁠[13] | The Baffin Bay and shocked-quartz papers' conclusions are not supported by their dating and sampling, so both are retracted. | Accepted | The notices give specific failures, and the authors' objection that the problems were procedural did not reverse them⁠[23]⁠[13]. | ## What would settle it A blind, multi-laboratory test of the main markers through complete, densely dated sections at the sites the proponents consider strongest, with the sampling plan and identification criteria fixed in advance, would settle reproducibility and uniqueness. The Lubbock Lake test is the model and needs repeating at sites such as Murray Springs and Blackwater Draw. A modern age-depth model for each claimed site, published with all dates, would settle synchrony. For the ice, osmium isotopes and a full platinum-group profile in a second Greenland core across the same decades, and a search for matching tephra, would decide between an iron meteorite and a volcanic source. A crater or a strewn field of the right age would change the picture; nothing of the kind has been found. ## Questions 0 of 7 questions are answered. **Key questions** [All 7](https://mysteriesdept.com/questions/key-questions?mystery=younger-dryas-impact) **0** [Did a catastrophe at about 12.8 ka cause the North American megafaunal extinctions and the end of Clovis?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X9HM392H/did-a-catastrophe-at-about-12-8-ka-cause-the-north-american) 0 of 0 sub-questions answered·0 Most likely: extinctions were driven by climate change and human hunting over a longer period; Clovis gave way to… **0** [Did an extraterrestrial impact or airburst occur at the onset of the Younger Dryas, about 12,800 years ago?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X8AJ1304/did-an-extraterrestrial-impact-or-airburst-occur-at-the) 0 of 2 sub-questions answered·0 Most likely: no impact or airburst occurred; the proposed markers are terrestrial or background cosmic material… **0** [What produced the platinum spike in the GISP2 ice core near the Younger Dryas onset?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X92023AG/what-produced-the-platinum-spike-in-the-gisp2-ice-core-near) 0 of 0 sub-questions answered·0 Open: 4 answers, none ahead **0** [What triggered the Younger Dryas cooling?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X99T2T4C/what-triggered-the-younger-dryas-cooling) 0 of 0 sub-questions answered·0 Most likely: meltwater from the retreating ice sheets weakened the Atlantic overturning circulation ## Evidence 42 findings [Did an extraterrestrial impact or airburst occur at the onset of the Younger Dryas, about 12,800 years ago?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X8AJ1304/did-an-extraterrestrial-impact-or-airburst-occur-at-the)11 findings [Airbursts and impacts from a large fragmenting comet deposited a synchronous boundary layer with impact…](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XA183EE5/airbursts-and-impacts-from-a-large-fragmenting-comet)Disputed +[Proponents report boundary-layer peaks at dozens of sites in North America, Europe, the Middle East and elsewhere.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XA922RG4/proponents-report-boundary-layer-peaks-at-dozens-of-sites-in)Suggestive +[A Bayesian model of 354 dates from 23 sections gives 12,835–12,735 cal BP and is consistent with synchrony.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XAGW6QP0/a-bayesian-model-of-354-dates-from-23-sections-gives-12)Suggestive −[Independent and blind tests did not reproduce the markers at the boundary, and found them at other levels.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XARP3WTK/independent-and-blind-tests-did-not-reproduce-the-markers-at)Supported −[Only 3 of the 29 claimed sites have age control placing the layer at the onset.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XB0G7CCW/only-3-of-the-29-claimed-sites-have-age-control-placing-the)Supported −[No crater dates to the onset; the Hiawatha structure is about 58 million years old.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XB8A7G9W/no-crater-dates-to-the-onset-the-hiawatha-structure-is-about)Established −[Two 2025 papers adding Baffin Bay cores and shocked quartz were retracted for failures of age model and sampling.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XBG43AKY/two-2025-papers-adding-baffin-bay-cores-and-shocked-quartz)Supported [No impact or airburst occurred; the proposed markers are terrestrial or background cosmic material…](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XBQY621Q/no-impact-or-airburst-occurred-the-proposed-markers-are)Most likely +[The Lubbock Lake blind test found microspherules and nanodiamonds low or absent at the boundary and abundant in a sample younger than 11,500 years.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XBZR4HB4/the-lubbock-lake-blind-test-found-microspherules-and)Supported +[Electron microscopy identified claimed nanodiamonds as graphene and graphene-oxide aggregates.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XC7J46QR/electron-microscopy-identified-claimed-nanodiamonds-as)Supported −[The GISP2 platinum spike has no agreed terrestrial source.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XCFC149Z/the-gisp2-platinum-spike-has-no-agreed-terrestrial-source)Supported [A small or differentiated extraterrestrial body (such as an iridium-poor iron meteorite) left the Greenland…](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XCQ621B8/a-small-or-differentiated-extraterrestrial-body-such-as-an)Still possible +[The GISP2 spike has Pt/Ir ratios above all known terrestrial and chondritic materials and very high Pt/Al ratios.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XCZ0731Q/the-gisp2-spike-has-pt-ir-ratios-above-all-known-terrestrial)Supported −[The spike lasts about 14 years, which fits a fissure eruption better than an instantaneous event.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XD6T6GFP/the-spike-lasts-about-14-years-which-fits-a-fissure-eruption)Suggestive [Is the claimed boundary layer the same age at every site?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X8JC0DHZ/is-the-claimed-boundary-layer-the-same-age-at-every-site)4 findings [The boundary layer at all sites dates to 12,835–12,735 cal BP within dating error.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XDPE63NW/the-boundary-layer-at-all-sites-dates-to-12-83512-735-cal-bp)Disputed +[Two statistical tests on modelled and unmodelled ages from 30 records are consistent with synchronous deposition within about 100 years.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XDY859AR/two-statistical-tests-on-modelled-and-unmodelled-ages-from)Suggestive [The claimed layers are of different ages, or their ages are not known well enough to say.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XE623WP9/the-claimed-layers-are-of-different-ages-or-their-ages-are)Most likely +[Several claimed sites have no age control, nearly a dozen use flawed age-depth interpolations, and several are directly dated outside the window.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XEDW7MYR/several-claimed-sites-have-no-age-control-nearly-a-dozen-use)Supported +[The retracted shocked-quartz paper omitted available dates, used dates spanning centuries and reported no age models.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XENP10QS/the-retracted-shocked-quartz-paper-omitted-available-dates)Supported +[Recalibrating the Baffin Bay foraminifera dates by the recommended method moves them outside the Younger Dryas.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XEXG4QJV/recalibrating-the-baffin-bay-foraminifera-dates-by-the)Supported [Are the proposed markers (microspherules, nanodiamonds, shocked quartz, meltglass) reproducible and diagnostic of impact?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X8T620G9/are-the-proposed-markers-microspherules-nanodiamonds-shocked)7 findings [The markers form only at the temperatures and pressures of impacts and airbursts, and they peak at the…](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XFD40S6P/the-markers-form-only-at-the-temperatures-and-pressures-of)Disputed +[About 700 SEM-EDS analyses of spherules from 18 sites are said to be inconsistent with volcanic, cosmic background, lightning or authigenic origins.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XFMY6725/about-700-sem-eds-analyses-of-spherules-from-18-sites-are)Suggestive +[Nanodiamonds were reported at 10 to 3,700 ppb in the boundary layer and not above or below.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XFWR4AH1/nanodiamonds-were-reported-at-10-to-3-700-ppb-in-the)Suggestive −[No standard criteria exist for identifying magnetic spherules, and the blind test found them in a non-boundary sample.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XG4J3J7A/no-standard-criteria-exist-for-identifying-magnetic)Supported −[Material presented as cosmic spherule fragments in the Baffin Bay paper was identified as foraminifera.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XGCC79S8/material-presented-as-cosmic-spherule-fragments-in-the)Supported [The markers are background cosmic dust, volcanic or anthropogenic spherules, fire products or misidentified…](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XGM601YH/the-markers-are-background-cosmic-dust-volcanic-or)Most likely +[The 2009 independent study found no support at seven sites, including two of the originals.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XGW059BP/the-2009-independent-study-found-no-support-at-seven-sites)Supported +[Claimed nanodiamonds were identified as graphene and graphene-oxide aggregates.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XH3T39J1/claimed-nanodiamonds-were-identified-as-graphene-and)Supported +[Osmium isotopes at Hall's Cave point to volcanic sources for the boundary anomalies.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XHBM1HNJ/osmium-isotopes-at-halls-cave-point-to-volcanic-sources-for)Suggestive [What produced the platinum spike in the GISP2 ice core near the Younger Dryas onset?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X92023AG/what-produced-the-platinum-spike-in-the-gisp2-ice-core-near)7 findings [An iridium-poor, highly differentiated iron meteorite.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XHV87VMD/an-iridium-poor-highly-differentiated-iron-meteorite)Still possible +[Superchondritic Pt/Al and fractionated Pt/Ir ratios exclude mantle and chondritic sources.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XJ326DWH/superchondritic-pt-al-and-fractionated-pt-ir-ratios-exclude)Supported −[The spike spans about 14 years.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XJAW7C5S/the-spike-spans-about-14-years)Suggestive [Fractionated gas condensates from an unidentified volcanic eruption, probably an Icelandic subglacial or…](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XJJP1YXQ/fractionated-gas-condensates-from-an-unidentified-volcanic)Still possible +[Platinum-group patterns in submarine volcanic gas condensates (Niuatahi-Motutahi, Tonga) resemble the spike.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XJTG3XHH/platinum-group-patterns-in-submarine-volcanic-gas)Suggestive +[Modern Pt spikes in ice and sediment are known from eruptions.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XK2A692F/modern-pt-spikes-in-ice-and-sediment-are-known-from)Suggestive −[No eruption has been identified for the interval.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XKA47XC2/no-eruption-has-been-identified-for-the-interval)Supported [The Laacher See eruption.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XKHY6GWP/the-laacher-see-eruption)Disputed −[New platinum and iridium data from the tephra do not match the spike.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XKSR1MN2/new-platinum-and-iridium-data-from-the-tephra-do-not-match)Supported −[The eruption is dated about 130 years before the onset.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XM1J224E/the-eruption-is-dated-about-130-years-before-the-onset)Supported [What triggered the Younger Dryas cooling?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X99T2T4C/what-triggered-the-younger-dryas-cooling)5 findings [Meltwater from the retreating ice sheets weakened the Atlantic overturning circulation.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XMH60RGT/meltwater-from-the-retreating-ice-sheets-weakened-the)Most likely +[The Younger Dryas resembles other abrupt cold events of the last deglaciation.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XMS078G5/the-younger-dryas-resembles-other-abrupt-cold-events-of-the)Supported +[The GISP2 record shows onset and end within decades, the pattern of circulation switches.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XN0T3EVS/the-gisp2-record-shows-onset-and-end-within-decades-the)Supported [Impact-driven fires and an impact winter tipped the climate.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XN8M37Y6/impact-driven-fires-and-an-impact-winter-tipped-the-climate)Disputed +[Ice-core combustion markers are said to show a biomass-burning episode at the onset.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XNGE2B10/ice-core-combustion-markers-are-said-to-show-a-biomass)Speculative −[Geomorphic, stratigraphic and fire records show no catastrophic change at the boundary.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XNR83V1Y/geomorphic-stratigraphic-and-fire-records-show-no)Supported [Volcanic forcing, from Laacher See or another eruption, pushed a system near a threshold.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XP0229RS/volcanic-forcing-from-laacher-see-or-another-eruption-pushed)Disputed −[Laacher See erupted about 130 years before the onset, too early to be its direct trigger.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XP7W3TG8/laacher-see-erupted-about-130-years-before-the-onset-too)Supported [Did a catastrophe at about 12.8 ka cause the North American megafaunal extinctions and the end of Clovis?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X9HM392H/did-a-catastrophe-at-about-12-8-ka-cause-the-north-american)3 findings [The impact's fires and climate effects killed off the megafauna and broke Clovis society within a short time.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XPQG4ZGZ/the-impacts-fires-and-climate-effects-killed-off-the)Disputed +[Last-appearance dates are consistent with extinction of many genera in a short window at the end of the Pleistocene.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XPZA6YDX/last-appearance-dates-are-consistent-with-extinction-of-many)Suggestive −[Archaeological data show no population decline or major adaptive shift at or just after 12.9 ka.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XQ7431RX/archaeological-data-show-no-population-decline-or-major)Supported [Extinctions were driven by climate change and human hunting over a longer period; Clovis gave way to…](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XQEY6VH6/extinctions-were-driven-by-climate-change-and-human-hunting)Most likely +[Late Pleistocene extinctions varied in time and space.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XQPR45S5/late-pleistocene-extinctions-varied-in-time-and-space)Supported [Do the two 2025 PLOS One papers, retracted in February 2026, still add evidence for an impact?](https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X9SE7KQA/do-the-two-2025-plos-one-papers-retracted-in-february-2026)5 findings [The data and conclusions stand; the problems were procedural and could have been corrected.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XR6C3ZJZ/the-data-and-conclusions-stand-the-problems-were-procedural)Disputed +[Lead author Christopher Moore said the group remains confident in the data, methods and conclusions.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XRE62HW5/lead-author-christopher-moore-said-the-group-remains)Speculative [The results do not support the conclusions because the age models, sampling and some identifications fail.](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XRP06ZVW/the-results-do-not-support-the-conclusions-because-the-age)Most likely +[Recommended calibration of the Baffin Bay dates gives younger ages outside the Younger Dryas, and one core has a non-boundary peak as large as the boundary peak in another.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XRXT584N/recommended-calibration-of-the-baffin-bay-dates-gives)Supported +[Supplementary material shown as cosmic spherule fragments was identified as foraminifera.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XS5M0V73/supplementary-material-shown-as-cosmic-spherule-fragments)Supported +[The shocked-quartz age model omitted available dates and the sections were not fully sampled.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XSDE2788/the-shocked-quartz-age-model-omitted-available-dates-and-the)Supported +[A co-author acknowledged at least 43 incorrect references.](https://mysteriesdept.com/mysteries/younger-dryas-impact/evidence/EVD0D51XSN8121C/a-co-author-acknowledged-at-least-43-incorrect-references)Supported ## Artifacts The films, photos, papers and objects this mystery rests on, each with its own key and its distance from the original. **Artifacts** [See all 14](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts) Photo1 step from object [The GISP2 ice core](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XXAE2580/the-gisp2-ice-core) NOAA · Public domain (US government work) Document2 steps from object [Boundary-layer sediment samples from the 2007 sites](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XY9P3QFB/boundary-layer-sediment-samples-from-the-2007-sites) Richard Firestone and colleagues · publisher Photo1 step from object [The "black mat" at Murray Springs](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XYSA1G8Y/the-black-mat-at-murray-springs) Ammodramus · CC0 Document2 steps from object [Quartz grains reported as shock-fractured (2025, retracted)](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XZ8Y2R89/quartz-grains-reported-as-shock-fractured-2025-retracted) James Kennett and colleagues · CC-BY-4.0 Photo2 steps from object [Melt glass from Abu Hureyra](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51XZRJ482C/melt-glass-from-abu-hureyra) Andrew M. T. Moore and colleagues · CC BY-SA 4.0 (as tagged on Commons; the source figure is CC BY 4.0) Photo2 steps from object [Radar survey and dated samples of the Hiawatha structure](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts/ART0D51Y0862A92/radar-survey-and-dated-samples-of-the-hiawatha-structure) NASA/Cindy Starr · Public domain (US government work) [See all 14 artifacts](https://mysteriesdept.com/mysteries/younger-dryas-impact/artifacts) ## See also [ **1908 Tunguska event** An explosion over the Siberian taiga in 1908 that flattened 2,150 km² of forest. ](https://mysteriesdept.com/mysteries/tunguska-event) [ **1979 Vela incident** A double flash seen by a US satellite over the South Atlantic in September 1979. ](https://mysteriesdept.com/mysteries/vela-incident) [ **Late Bronze Age collapse** The fall of the eastern Mediterranean palace states between about 1225 and 1150 BC. ](https://mysteriesdept.com/mysteries/bronze-age-collapse) [ **Roswell, 1947** Debris found near Roswell, New Mexico, in 1947 and announced as a flying disc. ](https://mysteriesdept.com/mysteries/roswell) ## References 1. 1.[Alley, R. 2000. The Younger Dryas cold interval as viewed from central Greenland. Quaternary Science Reviews 19(1–5), 213–226.](https://mysteriesdept.com/sources/SRC0D51WXJT0RPG/the-younger-dryas-cold-interval-as-viewed-from-central)[doi](https://doi.org/10.1016/S0277-3791(99)00062-1)cited 2 times here**SRC** 0D51WXJT0RPG 1. 2.[Green, C., Baldini, J., Brown, R. et al. 2025. A possible volcanic origin for the Greenland ice core Pt anomaly near the Bølling-Allerød/Younger Dryas boundary. PLOS One 20(9), e0331811.](https://mysteriesdept.com/sources/SRC0D51WX364VFQ/a-possible-volcanic-origin-for-the-greenland-ice-core-pt)[doi](https://doi.org/10.1371/journal.pone.0331811)cited 14 times here**SRC** 0D51WX364VFQ 1. 3.[Broecker, W., Denton, G., Edwards, R. et al. 2010. Putting the Younger Dryas cold event into context. Quaternary Science Reviews 29(9–10), 1078–1081.](https://mysteriesdept.com/sources/SRC0D51WXB01CDK/putting-the-younger-dryas-cold-event-into-context)[doi](https://doi.org/10.1016/j.quascirev.2010.02.019)cited 4 times here**SRC** 0D51WXB01CDK 1. 4.[Firestone, R., West, A., Kennett, J. et al. 2007. Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proceedings of the National Academy of Sciences 104(41), 16016–16021.](https://mysteriesdept.com/sources/SRC0D51WPR222ST/evidence-for-an-extraterrestrial-impact-12-900-years-ago)[doi](https://doi.org/10.1073/pnas.0706977104)cited 11 times here**SRC** 0D51WPR222ST 1. 5.[Wittke, J., Weaver, J., Bunch, T. et al. 2013. Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago. Proceedings of the National Academy of Sciences 110(23).](https://mysteriesdept.com/sources/SRC0D51WR6Y55NF/evidence-for-deposition-of-10-million-tonnes-of-impact)[doi](https://doi.org/10.1073/pnas.1301760110)cited 4 times here**SRC** 0D51WR6Y55NF 1. 6.[Moore, C., West, A., LeCompte, M. et al. 2017. Widespread platinum anomaly documented at the Younger Dryas onset in North American sedimentary sequences. Scientific Reports 7, 44031.](https://mysteriesdept.com/sources/SRC0D51WSE04C2D/widespread-platinum-anomaly-documented-at-the-younger-dryas)[doi](https://doi.org/10.1038/srep44031)cited 1 time here**SRC** 0D51WSE04C2D 1. 7.[Kennett, J., Kennett, D., Culleton, B. et al. 2015. Bayesian chronological analyses consistent with synchronous age of 12,835–12,735 Cal B.P. for Younger Dryas boundary on four continents. Proceedings of the National Academy of Sciences 112(32).](https://mysteriesdept.com/sources/SRC0D51WRYC7K4H/bayesian-chronological-analyses-consistent-with-synchronous)[doi](https://doi.org/10.1073/pnas.1507146112)cited 7 times here**SRC** 0D51WRYC7K4H 1. 8.[Surovell, T., Holliday, V., Gingerich, J. et al. 2009. An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis. Proceedings of the National Academy of Sciences 106(43), 18155–18158.](https://mysteriesdept.com/sources/SRC0D51WPZW3D1V/an-independent-evaluation-of-the-younger-dryas)[doi](https://doi.org/10.1073/pnas.0907857106)cited 5 times here**SRC** 0D51WPZW3D1V 1. 9.[Meltzer, D., Holliday, V., Cannon, M. et al. 2014. Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago. Proceedings of the National Academy of Sciences 111(21).](https://mysteriesdept.com/sources/SRC0D51WRER0TD5/chronological-evidence-fails-to-support-claim-of-an)[doi](https://doi.org/10.1073/pnas.1401150111)cited 6 times here**SRC** 0D51WRER0TD5 1. 10.[Holliday, V., Surovell, T., Johnson, E. 2016. A blind test of the Younger Dryas impact hypothesis. PLOS ONE 11(7), e0155470.](https://mysteriesdept.com/sources/SRC0D51WS6643R2/a-blind-test-of-the-younger-dryas-impact-hypothesis)[doi](https://doi.org/10.1371/journal.pone.0155470)cited 7 times here**SRC** 0D51WS6643R2 1. 11.[Holliday, V., Daulton, T., Bartlein, P. et al. 2023. Comprehensive refutation of the Younger Dryas Impact Hypothesis (YDIH). Earth-Science Reviews 247, 104502.](https://mysteriesdept.com/sources/SRC0D51WTWW7YV8/comprehensive-refutation-of-the-younger-dryas-impact)[doi](https://doi.org/10.1016/j.earscirev.2023.104502)cited 6 times here**SRC** 0D51WTWW7YV8 1. 12.[Sweatman, M., Powell, J., West, A. 2024. Rejection of Holliday et al.'s alleged refutation of the Younger Dryas impact hypothesis. Earth-Science Reviews 258, 104960.](https://mysteriesdept.com/sources/SRC0D51WV4P2DGW/rejection-of-holliday-et-al-s-alleged-refutation-of-the)[doi](https://doi.org/10.1016/j.earscirev.2024.104960)cited 2 times here**SRC** 0D51WV4P2DGW 1. 13.[The PLOS One Editors 2026. Retraction: A 12,800-year-old layer with cometary dust, microspherules, and platinum anomaly recorded in multiple cores from Baffin Bay. PLOS One 21, e0342613.](https://mysteriesdept.com/sources/SRC0D51WWBR25YC/retraction-a-12-800-year-old-layer-with-cometary-dust)[doi](https://doi.org/10.1371/journal.pone.0342613)cited 7 times here**SRC** 0D51WWBR25YC 1. 14.[The PLOS One Editors 2026. Retraction: Shocked quartz at the Younger Dryas onset (12.8 ka) supports cosmic airbursts/impacts contributing to North American megafaunal extinctions and collapse of the Clovis technocomplex. PLOS One 21, e0342620.](https://mysteriesdept.com/sources/SRC0D51WWKJ0X43/retraction-shocked-quartz-at-the-younger-dryas-onset-12-8-ka)[doi](https://doi.org/10.1371/journal.pone.0342620)cited 9 times here**SRC** 0D51WWKJ0X43 1. 15.[Petaev, M., Huang, S., Jacobsen, S. et al. 2013. Large Pt anomaly in the Greenland ice core points to a cataclysm at the onset of Younger Dryas. Proceedings of the National Academy of Sciences 110(32), 12917–12920.](https://mysteriesdept.com/sources/SRC0D51WQZ44MRA/large-pt-anomaly-in-the-greenland-ice-core-points-to-a)[doi](https://doi.org/10.1073/pnas.1303924110)cited 11 times here**SRC** 0D51WQZ44MRA 1. 16.[Reinig, F., Wacker, L., Jöris, O. et al. 2021. Precise date for the Laacher See eruption synchronizes the Younger Dryas. Nature 595, 66–69.](https://mysteriesdept.com/sources/SRC0D51WTD82RD0/precise-date-for-the-laacher-see-eruption-synchronizes-the)[doi](https://doi.org/10.1038/s41586-021-03608-x)cited 4 times here**SRC** 0D51WTD82RD0 1. 17.[Wolbach, W., Ballard, J., Mayewski, P. et al. 2018. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ~12,800 years ago. 1. Ice cores and glaciers. The Journal of Geology 126(2), 165–184.](https://mysteriesdept.com/sources/SRC0D51WSNT4DN9/extraordinary-biomass-burning-episode-and-impact-winter)[doi](https://doi.org/10.1086/695703)cited 3 times here**SRC** 0D51WSNT4DN9 1. 18.[Kennett, D., Kennett, J., West, A. et al. 2009. Nanodiamonds in the Younger Dryas boundary sediment layer. Science 323(5910), 94.](https://mysteriesdept.com/sources/SRC0D51WQFG1AQE/nanodiamonds-in-the-younger-dryas-boundary-sediment-layer)[doi](https://doi.org/10.1126/science.1162819)cited 2 times here**SRC** 0D51WQFG1AQE 1. 19.[Moore, A., Kennett, J., Napier, W. et al. 2020. Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas onset (~12.8 ka): high-temperature melting at >2200 °C. Scientific Reports 10, 4185.](https://mysteriesdept.com/sources/SRC0D51WSXM7KB9/evidence-of-cosmic-impact-at-abu-hureyra-syria-at-the)[doi](https://doi.org/10.1038/s41598-020-60867-w)cited 2 times here**SRC** 0D51WSXM7KB9 1. 20.[Daulton, T., Pinter, N., Scott, A. 2010. No evidence of nanodiamonds in Younger–Dryas sediments to support an impact event. 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