A cometary mechanism for the formation of tektites

Abstract

Passage of the Earth through a comet must occur on average once every million years approximately and last for a time of a few hours. A proportion of short-period comets will have had sufficiently small eccentricity (less than about 0.6) for accretion of cometary material to occur during such passages and produce a narrow jet of material projected vertically downwards through the atmosphere. The orbits of these comets are such that the jet would be most likely to fall within lower latitude, as is found for tektite-fields. The temperature within the accretion-stream would be sufficiently great to vaporize most materials, and the tektites are regarded as forming from the most refractory substances within the stream, so that they are not characteristic of cometary compositions. The speeds of entry into the atmosphere are high enough for ablation to occur, and the dimensions of the resulting fields (arising chiefly owing to the rotation of the Earth during the passage) and their total masses agree in general order of magnitude with those estimated for actual fields.