The Younger Dryas impact hypothesis: a cosmic catastrophe

Abstract

In this paper we review the evidence for the Younger Dryas impact hypothesis (YDIH), which proposes that at ∼12.9k cal a BP North America, South America, Europe and the Middle East were subjected to some sort of extraterrestrial event. This purported event is proposed as a catastrophic process responsible for: terminal Pleistocene environmental changes (onset of YD cooling, continent‐scale wildfires); extinction of late Pleistocene mammals; and demise of the Clovis ‘culture’ in North America, the earliest well‐documented, continent‐scale settlement of the region. The basic physics in the YDIH is not in accord with the physics of impacts nor the basic laws of physics. No YD boundary (YDB) crater, craters or other direct indicators of an impact are known. Age control is weak to non‐existent at 26 of the 29 localities claimed to have evidence for the YDIH. Attempts to reproduce the results of physical and geochemical analyses used to support the YDIH have failed or show that many indicators are not unique to an impact nor to ∼12.9k cal a BP. The depositional environments of purported indicators at most sites tend to concentrate particulate matter and probably created many ‘YDB zones’. Geomorphic, stratigraphic and fire records show no evidence of any sort of catastrophic changes in the environment at or immediately following the YDB. Late Pleistocene extinctions varied in time and across space. Archeological data provide no indication of population decline, demographic collapse or major adaptive shifts at or just after ∼12.9 ka. The data and the hypotheses generated by YDIH proponents are contradictory, inconsistent and incoherent.

Late Quaternary sea-level history and the antiquity of mammoths (Mammuthus exilisandMammuthus columbi), Channel Islands National Park, California, USA

“…Other investigators have pointed out the possibility of a combination of human-caused and climate-related causes of extinction (see discussion in Barnosky et al, 2004). Although all three mechanisms are controversial, the extraterrestrial impact hypothesis has received a significant amount of criticism (e.g., Daulton et al, 2010;Pinter et al, 1998Pinter et al, , 2011Holliday et al, 2014;Meltzer et al, 2014) and is not considered further here. No attempt is made to discuss the pros and cons of the human vs. climate change causes for megafaunal extinction in North America, but some of the findings presented here have relevance to the debate on these two causes for mammoth extinction specifically on the Channel Islands.…”

Widespread platinum anomaly documented at the Younger Dryas onset in North American sedimentary sequences

“…Specifically, questions have been raised regarding the nature or replicability of the reported impact proxies, the accuracy of the established chronology, and its purported effects on humans and animals at the YD onset12131415161718. All of these criticisms have been addressed by additional and independent studies replicating the original findings of Firestone et al 371920…”

Catastrophism through the Ages, and a Cosmic Catastrophe at the Origin of Civilization

“…Indeed, recent evidence from the last few years from three independent research groups has revealed a platinum anomaly that extends at least across North America, Greenland and North-West Europe, coeval with other evidence for a cosmic impact, including impact spherules, magnetic grains and nano diamonds [24][25][26]. Although disputed by several prominent and vocal research groups, their counter-arguments are generally weak to non-existent while evidence from independent research groups continues to accumulate [27][28][29][30][31][32][33][34].…”