The Younger Dryas Boundary (YDB): terrestrial, cosmic, or both?

The proposed cosmic-induced conflagration of the black mat (BM), at the end of the Aller & oslash;d interstade, dated to the 12.8 ka & mdash;Younger Dryas boundary (YDB), has been variably related to multiple airburst events following earth's encounter with the Encke Comet. Evidence for the BM, as on Mt. Viso in the Western Alps of Europe, and in the high northwestern Venezuelan Andes, relies upon variably distributed rock clasts, paleosols, and sediment resident in Late Glacial (LG) moraines, mass wasted deposits, and glaciolacustrine sediment. It is the age correlation of these two cosmic-affected sites & mdash;Viso-Andes & mdash;correlated with the 12,737 +/- 41 cal yr BP upper YD age glaciolacustrine sediment of Kr & aring;kenes, Norway, and readjused pollen sites to 12,820 yr BP that has not been discussed in terms of contemporaneity & mdash;cosmic-terrestrial. The cosmic theory termed the YD impact hypothesis & mdash;YDIH & mdash;has witnessed slow acceptance by the scientific community, compared with century long attention paid to the YD terrestrially oriented hypotheses. The cosmic-affected LG sediment (Viso), with AMS C14 dated glaciofluvial sediment in the northern Andes, place the upper YD aligned with black mat dated sediment on several continents. As well, the cosmic hypothesis supporting the YD covers wider spatial ground compared with terrestrial arguments and is likely a progenitor of this one major climatic shift of the Neogene. Previous workers on the YD climatic shift, as outlined here, may have overlooked, or overreached to explain, the BM occurrence. Firming up the YDIH to the YDB parallels similar past struggles with continental drift to plate tectonics, crater age chronology theories on Mars, Agassiz's ice age theory, and human-induced climatic warming. Time perhaps, to bring the terrestrially driven explanation for the YDB to the YDIH, the latter was continually supported by a number of independent studies.