PP43A-06 The Younger Dryas ET Impact Theory and Terminal Pleistocene Mammalian Extinctions in North AmericaPP05: New Insights into Younger Dryas Climatic Instability, Mass Extinction, the Clovis People, and Extraterrestrial ImpactsDespite decades of intensive study and debate, no consensus has been reached on what caused the extinction of North America's mammalian megafauna at the end of the Pleistocene. In a scholarly standoff, prominent scientists have shown that neither "human overkill" or "climate change" models adequately account for the patterns found in the paleontological and archaeological records of North America. The Younger Dryas ET Impact theory may dramatically alter this debate, adding a catastrophic trigger to help explain the rapid extinction of many large mammals about 12,900 years ago. New data suggest that an extraterrestrial impact focused in northern and eastern North America may have devastated the megafauna through: (1) direct mortality caused by the impacts shock wave, debris, and massive wildfires; (2) dramatic reduction of terrestrial food supplies, rapid climatic change, and ecological reorganization; and (3) coup-de-grace effects of surviving human populations rapidly expanding after the impact.
The deglaciation that followed the last ice age period was abruptly and dramatically interrupted ~12,900 years ago by widespread cooling that marks the onset of the Younger Dryas Cool Episode, an apparent climatic anomaly in Quaternary deglaciation behavior. Much evidence shows that the Younger Dryas onset was marked by abrupt changes in ice sheet configuration, diversion of North American flood-waters to the northern Atlantic, the sudden emptying of proglacial lakes, and the reorganization of thermohaline circulation that may have triggered severe cooling. Nevertheless, significant questions have recently emerged about timing and direction of major freshwater flows to the oceans, in turn raising questions about the triggering mechanism for the Younger Dryas. The onset of the Younger Dryas also appears to have coincided with massive, widespread and punctuated changes in animal biota and Paleolithic cultural development centered in North and South America. This is represented by the well-known extinction of the megafauna of the Americas, including mammoths, horses and groundsloths (the most recent of all mass extinctions) and the termination of Clovis and certain other contemporaneous Paleolithic human cultures. The cause of these changes is also highly controversial and much debated, but is likely tied to the severe environmental changes that occurred at the beginning of the Younger Dryas. Nevertheless, some researchers consider these to be coincidental events, while others link the two as cause and effect. Another hypothesis attributes the extinctions to overhunting by Clovis people and other Paleolithic hunters or to pandemics associated with human migrations. However, all these hypotheses appear to fall short in satisfactorily explaining much available evidence. A new hypothesis posits that Younger Dryas cooling was instead triggered by extraterrestrial impacts that caused ice sheet destabilization, flood-water rediversion and changes in ocean circulation. This work offers newly uncovered evidence for ET impact at 12.9 ka including end-Clovis age sediments throughout North America with high levels of Iridium, magnetic and carbon, spherules, glass-like carbon, fullerenes, and ET noble gas ratios often in association with carbonaceous black layers and succeeded by black mats with unusual biota In this session, we invite abstracts that will explore the strengths and weaknesses of existing and new hypotheses that attempt to explain the cause of the Younger Dryas and of associated changes in the global environmental system, the associated extinctions, and of human cultural changes. We welcome all abstracts exploring new perspectives on the chronology, stratigraphic succession and potential interconnections between a wide-range of processes that appear to have been associated with the Younger Dryas Episode. These include abrupt climatic change, ice-sheet deglaciation, flood-water rerouting, surficial geology, iceberg discharge, ocean reorganization including thermohaline circulation, and sea-level change. Also critical is the timing and nature of major extinction, Paleolithic cultural succession and impact-related phenomena.
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Notice that he is actually INVITING criticism and debate on this thesis? Instead of warning that those who disagree should be fired as reactionary extremists.