Origin of tektites:  an alternative to terrestrial impact theory.
The Terrestrial Impact Theory (TIT) has won a complete victory over O'Keefe's lunar volcanic theory, but only because the Moon appears to be the wrong place for tektites. Indeed, the TIT ignores strong evidence of their volcanic origin--far from the Moon. The Extraterrestrial Volcanic Comet Theory proposes an alternative to both of these theories.  Major arguments for an extraterrestrial tektite source are paradoxical: a great time difference between tektite formation and their arrival on Earth, and also forms, plastic deformations, ice collision marks, vacuum voids, etc. indicating specific conditions of tektite formation such as low gravitational field, lack of atmosphere, interaction of hot plastic tektites with ice, etc. Major evidence of volcanic origin includes: close analogy between shaped tektites and small volcanic bombs, and between layered tektites and lava or tuff-lava flows or huge bombs; analogy between flanged tektites and volcanic bombs ablated by gasjets: long-time, multistage formation of some tektites that corresponds to wide variations in their radiometric ages; well-ordered long compositional trends (series) typical of magmatic differentiation; different compositional tektite families (subseries) comparable to different stages (phases) of the volcanic process. Thus, different types of volcanic eruptions under extraterrestrial conditions could be reconstructed based on tektite properties. It is presumed that tektites were transported to the Earth by specific eruptive comets, i.e. in the form of ice-tektite agglomerates launched into space by volcanic explosion. Major arguments favouring comets include: ice collision marks and imprints as mentioned above; linear band-like sculpture of the Australasian strewn field as evidence of comet fragmentation and slope or skipping trajectory of separate fragments; compact coincidence of the Zhamanshin impact crater with small tektite strewn field as evidence of steep trajectory of separate comet fragments that disintegrated while entering the atmosphere. The comet-Earth collision under consideration happened 10,000 years ago and caused the global catastrophe marked by the sharp Pleistocene-Holocene boundary, i.e. by abrupt climatic changes, the end of glaciation, mass extinction, etc. This event can be compared with the "dinosaur" catastrophe at the K/T boundary 65 Ma, which was also accompanied by tektite fall.
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United Institute of Geology, Geophysics and Mineralogy, Russian Academy of Sciences, Siberian Branch, Novosibirsk, Russia.
D018534:Earth, Planet; D005118:Extraterrestrial Environment; D005580:Fossils; D055593:Geological Phenomena; D005844:Geology; D005898:Glass; D007053:Ice; D019110:Meteoroids; D010163:Paleontology; D018707:Volcanic Eruptions
D007053:Ice