Evidence of Cosmic Impact at Abu Hureyra, Syria at the Younger Dryas Onset (similar to 12.8 ka): High-temperature melting at > 2200 degrees C
Abstrakt
At Abu Hureyra (AH), Syria, the 12,800-year-old Younger Dryas boundary layer (YDB) contains peak abundances in meltglass, nanodiamonds, microspherules, and charcoal. AH meltglass comprises 1.6 wt.% of bulk sediment, and crossed polarizers indicate that the meltglass is isotropic.
High YDB concentrations of iridium, platinum, nickel, and cobalt suggest mixing of melted local sediment with small quantities of meteoritic material. Approximately 40% of AH glass display carbon-infused, siliceous plant imprints that laboratory experiments show formed at a minimum of 1200 degrees-1300 degrees C; however, reflectance-inferred temperatures for the encapsulated carbon were lower by up to 1000 degrees C.
Alternately, melted grains of quartz, chromferide, and magnetite in AH glass suggest exposure to minimum temperatures of 1720 degrees C ranging to >2200 degrees C. This argues against formation of AH meltglass in thatched hut fires at 1100 degrees-1200 degrees C, and low values of remanent magnetism indicate the meltglass was not created by lightning.
Low meltglass water content (0.02-0.05% H2O) is consistent with a formation process similar to that of tektites and inconsistent with volcanism and anthropogenesis. The wide range of evidence supports the hypothesis that a cosmic event occurred at Abu Hureyra similar to 12,800 years ago, coeval with impacts that deposited high-temperature meltglass, melted microspherules, and/or platinum at other YDB sites on four continents.