Editing Younger Dryas impact hypothesis (section)

=== "Black mats" ===
The evidence given by proponents of a [[bolide]] or [[meteorite]] impact event includes "black mats", or [[stratum|strata]] of organic-rich [[soil]] that have been identified at about 50 [[archaeological site]]s across North America.{{efn|name=Black mat note|The darkened [[stratum]] was first identified at the [[Lehner Mammoth-Kill Site]] by [[Emil Haury]] who named it "Lehner swamp soil";<ref>{{Cite Q |Q59224169 |author-link1=Emil Haury |last=Haury |first=Emil W. |last2=Sayles |first2=E. B. |last3=Wasley |first3=William W. |name-list-style=vanc}}</ref> it was later renamed by [[Vance Haynes#"Black mat" layers|Vance Haynes]] as the "black mat".<ref>{{Cite web |title= Paleoindian Studies and Geoarchaeology at the University of Arizona |url=http://www.argonaut.arizona.edu/history.htm |url-status=dead |archive-url=https://web.archive.org/web/20180723064120/http://www.argonaut.arizona.edu/history.htm |archive-date=2018-07-23 |website=[[University of Arizona]] |quote=Vance Haynes later renamed it the 'black mat'}}</ref><ref name="PNAS07A" />}} Using statistical analysis and modeling, [[James P. Kennett]] and others concluded that widely separated organic-rich layers, including ''black mats'', were deposited synchronously across multiple continents as an identifiable ''Younger Dryas boundary layer''.<ref>{{Cite Q|Q35718070|last1=Kennett|first1=James P|last2=Kennett|first2=Douglas J|last3=Culleton|first3=Brendan J|last4=Tortosa|first4=J Emili Aura|last5=Bischoff|first5=James L|last6=Bunch|first6=Ted E|last7=Daniel|first7=I Randolph|last8=Erlandson|first8=Jon M|last9=Ferraro|first9=David|last10=Firestone|first10=Richard B|last11=Goodyear|first11=Albert C|last12=Israde-Alcántara|first12=Isabel|last13=Johnson|first13=John R|last14=Pardo|first14=Jesús F Jordá|last15=Kimbel|first15=David R|last16=LeCompte|first16=Malcolm A|last17=Lopinot|first17=Neal H|last18=Mahaney|first18=William C|last19=Moore|first19=Andrew M T|last20=Moore|first20=Christopher R|last21=Ray|first21=Jack H|last22=Stafford|first22=Thomas W|last23=Tankersley|first23=Kenneth Barnett|last24=Wittke|first24=James H|last25=Wolbach|first25=Wendy S|last26=West|first26=Allen|author-link1=James P. Kennett|author-link8=Jon M. Erlandson|author-link11=Albert Goodyear|author-link19=Andrew M. T. Moore|display-authors=8|name-list-style=vanc}}</ref> In 2019, Jorgeson and others tested this conclusion with the simulation of radiocarbon ages.<ref name="JorgesonOthers2020a">{{Cite journal |last1=Jorgeson |first1=Ian A. |last2=Breslawski |first2=Ryan P. |last3=Fisher |first3=Abigail E. |name-list-style=vanc |date=13 February 2020 |title=Radiocarbon simulation fails to support the temporal synchroneity requirement of the Younger Dryas impact hypothesis |url=https://www.cambridge.org/core/journals/quaternary-research/article/abs/radiocarbon-simulation-fails-to-support-the-temporal-synchroneity-requirement-of-the-younger-dryas-impact-hypothesis/6478BF9FD2E63B22C6152075E1B5C089 |url-status=live |journal=[[Quaternary Research]] |volume=96 |pages=123–139 |bibcode=2020QuRes..96..123J |doi=10.1017/qua.2019.83 |issn=1096-0287 |archive-url=https://web.archive.org/web/20210620182032/https://www.cambridge.org/core/journals/quaternary-research/article/abs/radiocarbon-simulation-fails-to-support-the-temporal-synchroneity-requirement-of-the-younger-dryas-impact-hypothesis/6478BF9FD2E63B22C6152075E1B5C089 |archive-date=20 June 2021 |s2cid=213657406}}</ref> They accounted for measurement error, calibration uncertainty, "[[old wood]]" effects, and laboratory measurement biases, and compared against the dataset of radiocarbon ages for the [[Laacher See]] eruption. They found the Laacher See 14C dataset to be consistent with expectations of synchroneity. They found the Younger Dryas boundary layer 14C dataset to be inconsistent with the expectations for its synchroneity, and the synchronous global deposition of the hypothesized Younger Dryas boundary layer to be extremely unlikely.<ref name="JorgesonOthers2020a" />