Radiocarbon simulation fails to support the temporal synchroneity requirement of the Younger Dryas impact hypothesis

Jorgeson, Ian; Breslawski, Ryan P.; Fisher, Abigail

doi:10.1017/qua.2019.83

Cited by 24 publications

(6 citation statements)

References 71 publications

(97 reference statements)

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“…(69), as calibrated by IntCal13 (70), or between ∼12,875 and 12,775 B.P., as calibrated by IntCal20 (71). While this YDB age range agrees within error margin with the YD onset at 12,870 ± 30 B.P., a most recent simulation work demonstrates that this set of 14 C samples are extremely unlikely to have been deposited synchronously, calling into question the YD Impact Hypothesis (72). As such, it would be ideal to find the presumably large-scale extraterrestrial signal directly from Greenland ice cores to test its causal link to the YD event without the restraint of age uncertainty.…”

Section: Resultsmentioning

confidence: 82%

Timing and structure of the Younger Dryas event and its underlying climate dynamics

Cheng

Zhang

Spötl

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

145

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The Younger Dryas (YD), arguably the most widely studied millennial-scale extreme climate event, was characterized by diverse hydroclimate shifts globally and severe cooling at high northern latitudes that abruptly punctuated the warming trend from the last glacial to the present interglacial. To date, a precise understanding of its trigger, propagation, and termination remains elusive. Here, we present speleothem oxygen-isotope data that, in concert with other proxy records, allow us to quantify the timing of the YD onset and termination at an unprecedented subcentennial temporal precision across the North Atlantic, Asian Monsoon-Westerlies, and South American Monsoon regions. Our analysis suggests that the onsets of YD in the North Atlantic (12,870 ± 30 B.P.) and the Asian Monsoon-Westerlies region are essentially synchronous within a few decades and lead the onset in Antarctica, implying a north-to-south climate signal propagation via both atmospheric (decadal-time scale) and oceanic (centennial-time scale) processes, similar to the Dansgaard–Oeschger events during the last glacial period. In contrast, the YD termination may have started first in Antarctica at ∼11,900 B.P., or perhaps even earlier in the western tropical Pacific, followed by the North Atlantic between ∼11,700 ± 40 and 11,610 ± 40 B.P. These observations suggest that the initial YD termination might have originated in the Southern Hemisphere and/or the tropical Pacific, indicating a Southern Hemisphere/tropics to North Atlantic–Asian Monsoon-Westerlies directionality of climatic recovery.

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Section: Resultsmentioning

confidence: 82%

Timing and structure of the Younger Dryas event and its underlying climate dynamics

Cheng

Zhang

Spötl

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

145

View full text Add to dashboard Cite

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“…Finally, Jorgeson et al (2020) find the dispersion in radiocarbon dates from measurements from within the YDB layer only is greater than those from within the Laacher See boundary layer (the Laacher See volcanic eruption occurred in the region of modern Germany, probably around 100 years earlier than the Younger Dryas event (Kletetschka et al, 2018)). However, they don't include the new measurements taken from the YDB at Lake Hind by Teller et al (2020),and they only allow for 'old wood' at Arlington Canyon on Santa Rosa Island up to 100 years old, which seems inadequate given the likely age of trees that grew there.…”

Section: Synchroneitymentioning

confidence: 85%

The Younger Dryas impact hypothesis: Review of the impact evidence

Sweatman

2021

Earth-Science Reviews

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Firestone et al., 2007, PNAS 104(41): 16016-16021, proposed that a major cosmic impact, circa 10,835 cal. BCE, triggered the Younger Dryas (YD) climate shift along with changes in human cultures and megafaunal extinctions. Fourteen years after this initial work the overwhelming consensus of research undertaken by many independent groups, reviewed here, suggests their claims of a major cosmic impact at this time should be accepted. Evidence is mainly in the form of geochemical signals at what is known as the YD boundary found across at least four continents, especially North America and Greenland, such as excess platinum, quench-melted materials, and nanodiamonds. Their other claims are not yet confirmed, but the scale of the event, including extensive wildfires, and its very close timing with the onset of dramatic YD cooling suggest they are plausible and should be researched further. Notably, arguments by a small cohort of researchers against their claims of a major impact are, in general, poorly constructed, and under close scrutiny most of their evidence can actually be interpreted as supporting the impact hypothesis.

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“…Their presentation was followed by a flurry of articles and papers (e.g., Firestone et al 2007aFirestone et al , 2007bFirestone et al , 2008Kennett et al 2008aKennett et al , 2008bKennett et al , 2009Kennett et al , 2015Kinzie et al 2014;Wittke et al 2013;Kletetschka et al 2018;Moore et al 2017Moore et al , 2019. The putative impact evidence was disputed in a slew of anti-impact papers (Pinter and Ishman 2008;Paquay et al 2009;Surovell et al 2009;Fiedel 2010;Holliday and Meltzer 2010;Pinter et al 2011b;Boslough et al 2012;Pigati et al 2012;van Hoesel et al 2012van Hoesel et al , 2014Holliday et al 2014;Scott et al 2016;Daulton et al 2017;Roperch et al 2017;Holliday et al 2020;Jorgeson et al 2020;Sun et al 2020). The debate continues with no prospect of imminent resolution.…”

Section: Initial Human Colonization 867mentioning

confidence: 99%

Initial Human Colonization of the Americas, Redux

Fiedel¹

2022

Radiocarbon

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The study of the peopling of the Americas has been transformed in the past decade by astonishing progress in paleogenomic research. Ancient genomes now show that Native American ancestors were formed in Siberia or the Amur region by admixture of ca. 15–30% Ancient North Eurasian genes with those of East Asians. The Anzick infant, buried with Clovis bifaces at 12,900 cal BP, belonged to a group that was ancestral to later Native Central and South Americans. Fishtail points, derived from Clovis, mark the arrival and rapid expansion of Clovis-descended Paleoindians across South America, also evident in the sharp increase of radiocarbon dates, continent-wide, at 13,000–12,500 cal BP. In both North and South America, extinction of most genera of megafauna was virtually simultaneous with Paleoindian expansion. Human hunting must have been involved, perhaps in concert with other indirect impacts. Contrary to the alternative bolide impact theory, there is no evidence of a dramatic human population decline after 12,800 cal BP. Ancient genomes show that divergent lithic traditions after 13,000 cal BP need not be attributed to a separate Pacific Rim migration stream. Several recent finds raise the possibility that pre-Clovis people might have reached the Americas before 20,000 cal BP, but these precursors must have either failed to thrive, or were ultimately replaced by proto-Clovis or Clovis people. Consilient paleogenomic and archaeological data indicate that initial colonization by Paleoindian ancestors of living Native Americans occurred after 14,500 cal BP.

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Radiocarbon simulation fails to support the temporal synchroneity requirement of the Younger Dryas impact hypothesis

Cited by 24 publications

References 71 publications

Timing and structure of the Younger Dryas event and its underlying climate dynamics

Timing and structure of the Younger Dryas event and its underlying climate dynamics

The Younger Dryas impact hypothesis: Review of the impact evidence

Initial Human Colonization of the Americas, Redux

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