The Encke Comet Impact/Airburst and the Younger Dryas Boundary: Testing the Impossible Hypothesis (YDIH)

Abstract

Many have tagged the Younger Dryas Impact Hypothesis, (YDIH) an ethereal expression to explain the Younger Dryas (YD) climatic reversal, namely the Younger Dryas Boundary (YDB), a theory, deniers state, lacking convincing evidence in support. The core of the hypothesis lies squarely on anti-uniformitarianism, that is, uniform processes moving uniformly with no room for catastrophic events, specifically cosmic catastrophic forces. Beyond philosophically based aversion to the YDIH, specific criticism comes from megafauna and archaeologic corners, related to the near coeval disappearance of specific Late Pleistocene species on the one hand, and relation to disruption and temporary disappearance of the Clovis people on the other. Coupled to all this, breakup of the Laurentide Ice Sheet (LIS) and resultant Lake Agassiz-Mackenzie River floods, disrupting the thermohaline circulation of the North Atlantic, all meltwater induced marine coupled atmospheric cooling is at the heart of the Late Glacial/Younger Dryas transition. In short, deniers of the cosmic link—the black mat----use geohydrologic explanations to explain the foremost climatic reversal of the Late Pleistocene. The geologic paradigm, firmly in place with meltwater release into the Atlantic in tow, attention slowly drifted to explanation of an innocuous looking, thin (~ 1–2 cm), black sediment bed found in lacustrine and fluvial deposits of the American southwest, and other places. Thus, with thin dark beds of Gubbio in mind, the quest to explain black mat (BM) beds took on a cosmic aspect, one with growing, supporting evidence on several continents. The impossible hypothesis, now the probable explanation of the YD climatic reversal, is at center stage, set at 12.8 ka, with a burgeoning corpus of undeniable evidence its cornerstone. It is this undeniable evidence that is the subject of this paper.