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Trust but Verify: Independent confirmations of the Younger Dryas Impact Boundary
event December 4, 2011 comment 19 Comments

Skeptics of the YDIB hypothesis frequently state that no one can reproduce the YDIB results(Kerr, 2010);nobody has found anything(Kerr, 2010); there is a lack of reproducibility of data (Holliday, 2011); and unique peaks in concentrations at the YD onset have yet to be reproducedPinter (2011). These casual dismissals are hurtful to the investigation, demonstrably false, and irresponsible. That independent researchers have identified materials diagnostic of an event of cosmic proportions at 12.9 before present should not be subject to debate.

To wit, I offer below citations of published research confirming the original findings of Firestone, et. al. in 2007. Note that some of these researchers disagree with an extraterrestrial impact as cause and offered alternate hypotheses, but, in every case, those speculating about causation have not conducted any analytical work to determine if their hypotheses are correct.

INDEPENDENT GROUPS with positive results:



Baker et al. (2008)

Fayek (2008)

Ge et al. (2009, page 1)

Haynes et al. (2010, page 1)

LeCompte et al. (2010)

Mahaney (2010a, page 10)

Wu (2011)

Fayek (2011)


Ge et al. (2009, page 1)

Tankersley (2009)

Tian (2010, page 1)

Van Hoesel (2011)

Bement et al. (2011)


Beets et al. (2008, page 1)

Sharma et al. (2009)

Haynes et al. (2010, page 1)

Mahaney (2010a, page 10)

Marshall (2011)

Wu (2011)

Andronikov (2012)


Mahaney (2010a, page 10)

Tian (2010, page 1)

Courty et al. (2010)

Ge et al. (2009, page 1)

Baker et al. (2008, page 1)

Tankersley (2009)


Mahaney et al. (2010b)

Ge et al. (2009)

Courty et al. (2010)



Schroeder (2009)

Steele (2010)


Higgins, et al. (2011)



Baker DW, Miranda PJ, Gibbs KE. (2008) Montana Evidence for Extra-Terrestrial Impact Event That Caused Ice-Age Mammal Die-Off. American Geophysical Union, Spring Meeting 2008, abstract #P41A-05.

Beets C, Sharma M, Kasse K, Bohncke S. (2008) Search for Extraterrestrial Osmium at the Allerod – Younger Dryas Boundary. American Geophysical Union, Fall Meeting 2008, abstract #V53A-2150.

Bement L, Carter BJ, Simms A, Madden A. (2011) The Bull Creek valley stream terraces, buried soils, and paleo-environment during the Younger Dryas in the Oklahoma Panhandle, USA. Paper #1447, XVIII INQUA-Congress, 21-27 July 2011 in Bern, Switzerland.

Bunch Ted E., James Wittke, Allen West, James Kennett. (2011) Shock-melt Evidence for a Cosmic Impact with Earth during the Younger Dryas at 12.9 ka. Abstract 1606, Session 60, XVIII INQUA-Congress, 21-27 July 2011 in Bern, Switzerland.

Courty MA, Fedoroff M. (2010) Soil morphologic indicators of environmental hazards linked to cosmic airburst. 19th World Congress of Soil Science, Brisbane.

Daulton T, Pinter N, Scott A (2010) “No evidence of nanodiamonds in Younger-Dryas sediments to support an impact event”. Proceedings of the National Academy of Sciences of the United States of America 107 (37): 16043–16047

Fayek, M.; Hull, S.; Anovitz, L.; Haynes, V.; Bergen, L. (2008) Evidence of impact material and the extinction of the mega-fauna 12,900 years ago. American Geophysical Union, Fall Meeting 2008, abstract #PP13C-1469.

Firestone RB, et al. (2007) Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proc Natl Acad Sci USA 104:16016–16021.

Firestone RB. (2009) The Case for the Younger Dryas Extraterrestrial Impact Event: Mammoth, Megafauna, and Clovis Extinction, 12,900 Years Ago. Journal of Cosmology (

Ge T, Courty MM, Guichard F (2009) Field-Analytical approach of land-sea records for elucidating the Younger Dryas Boundary syndrome. American Geophysical Union, Fall Meeting 2009, abstract #PP31D-1390.

Haynes CV, Jr, Lauretta DS, Ballenger JAM. (2010) Reply to Firestone et al.: No confirmation of impact at the lower Younger Dryas boundary at Murray Springs, AZ. Proceedings of the National Academy of Sciences, vol. 107, issue 26, pp. E106-E106.

Holliday V. (2011) A Cosmic Catastrophe: the Great Clovis Comet Debate.

Kennett DJ, et al. (2009a) Shock-synthesized hexagonal diamonds in Younger Dryas boundary Sediments, Proc Natl. Acad. Sci. USA, 106 (31): 12623-12628.

Kennett DJ, et al. (2009b) Nanodiamonds in the Younger Dryas boundary sediment layer. Science 323:94.

Kerr RA. (2010) Mammoth-Killer Impact Flunks Out. Science 3 September 2010: 1140-1141.

LeCompte MA, Goodyear AC, Demitroff M, Batchelor D, Mooney C. (2010) An Independent Review of the Younger Dryas Extraterrestrial Impact Hypothesis and its Recent Re-Evaluation by Surovell et al. 21st Biennial Meeting of the American Quaternary Association (AMQUA). Laramie, Wyoming.

Mahaney WC, et al. (2010a) Evidence from the northwestern Venezuelan Andes for extraterrestrial impact: The black mat enigma. Geomorphology, v. 116, iss. 1-2, p. 48-57.

Mahaney WC, Krinsley D, Kalm V (2010b) Evidence for a cosmogenic origin of fired glaciofluvial beds in the northwestern Andes: Correlation with experimentally heated quartz and feldspar. Sedimentary Geology, v. 231, iss. 1-2, p. 31-40.

Mahaney WC, David Krinsley, Kurt Langworthy, Kris Hart, Volli Kalm, Pierre Tricart and Stephane Schwartz. (2011a) Fired glaciofluvial sediment in the northwestern Andes: Biotic aspects of the Black Mat. Sedimentary Geology. 237, (1-2), pp73-83.

Mahaney, WC, Dave Krinsley, James Dohm, Volli Kalm, Kurt Langworthy and J. Ditto. (2011b) Notes on the black mat sediment, Mucunuque Catchment, northern Mérida Andes, Venezuela.. Journal of Advanced Microscopic Research, vol. 6, no. 3.

Marshall W, Head K, Clough R, Fisher A. (2011) Exceptional iridium concentrations found at the Allerød-Younger Dryas transition in sediments from Bodmin Moor in southwest England. Paper #2641, XVIII INQUA-Congress, 21-27 July 2011 in Bern, Switzerland.

McDonough W, Sun S (1995) The composition of the Earth. Chem Geol 120:223–253.

Pinter N, et al. (2011) The Younger Dryas impact hypothesis: A requiem, Earth Science Reviews (in press).

Schroeder KB. (2009) Haplotypic background of a private allele at high frequency in the Americas. Molecular biology and evolution 2009;26(5):995-1016.

Scruggs, MA, Raab LM, Murowchick JS, Stone MW, Niemi TM. (2010) Investigation of Sediment Containing Evidence of the Younger Dryas Boundary (YPB) Impact Event, El Carrizal, Baja California Sur, Mexico. Geological Society of America Abstracts with Programs, Vol. 42, No. 2, p. 101.

Sharma M, Chen C, Jackson BP, Abouchami W. (2009) High resolution Osmium isotopes in deep-sea ferromanganese crusts reveal a large meteorite impact in the Central Pacific at 12 ± 4 ka. American Geophysical Union, Fall Meeting 2009, abstract #PP33B-06.

Steele J. (2010) Radiocarbon dates as data: quantitative strategies for estimating colonization front speeds and event densities. Journal of Archaeological Science 37/8, p. 2017-2030.

Surovell TA, et al. (2009) An Independent Evaluation of the Younger Dryas Extraterrestrial Impact Hypothesis. Proc. Natl. Acad. Sci. USA, 104: 18155–18158.

Tankersley K. (2009) “Evidence of the Clovis Age Comet at Sheriden Cave, Ohio.” Midwest Chapter of the Friends of Mineralogy Symposium and Field Conference (Geology Department of Miami University, Oxford, Ohio, USA), 5 September 2009.

Tian H, Schryvers D, Claeys P (2011) Nanodiamonds do not provide unique evidence for a Younger Dryas impact. Proceedings of the National Academy of Sciences, vol. 108, issue 1, pp. 40-44.

Van der Hammen T., van Geel B. (2008) Charcoal in soils of the Allerød-Younger Dryas transition were the result of natural fires and not necessarily the effect of an extra-terrestrial impact. Netherlands Journal of Geosciences, vol. 87, 4, pp. 359-361.

Van Hoesel A, Hoek W, Braadbaart F, van der Plicht H, Drury MR. (2011) Nanodiamonds and the Usselo layer. Paper #1556, XVIII INQUA-Congress, 21-27 July 2011 in Bern, Switzerland.

Wu Y. (2011) Origin and Provenance of Magnetic Spherules at the Younger Dryas Boundary. Thesis, Dartmouth College.

black mat independent confirmations Iridium Richard Kerr science magazine support for hypothesis younger dryas younger dryas boundary