You are at the A. Ol'khovatov www-page: www.olkhov.narod.ru/tunguska/tektites.htm
The last update: August 5, 1999.
The problem of the tektites formation is not resolved. I think that for
those, who are interested in tektites, maybe it would be interesting to
read my note (below), which I submitted in the spring of 1998 to one
astronomical magazine, and which was rejected by a peer-reviewer.
In brief, the note (below) describes the events which resemble some types of tektites production on mini-scale and evidently without any meteorite impact.
The problem of tektites formation is still unresolved. Many years ago it was supposed they are formed due to lightning strikes. Today it is inclined to think that they are formed during giant meteoroid impacts. Nevertheless this idea also has its shortcomings (see METEORITE! February 1998, p.36).
Below the author presents several natural events which resemble the tektite formation on mini-scale, or at least, a Muong Nong type of tektites and Libyan Desert Glass-type formations.
The first one is discovering of an area with dimentions 3.5m * 5.5m of molten sand in the Kizilkum desert (former Soviet Middle Asia). It was surrounded by an area 14.5m * 8.5m of burnt (scorched) vegetation. When it was first seen in October, 1990 the majority of the area was covered by solid (unbroken) grey-colored glass film with scattered drops of glass. When a research by geologist V. Sal'nikov with colleagues was conducted in September, 1991, the glass 'bubbled' cover (1-2 cm thickness) was cracked. Below the glass there was a usual sand. Chemical analysis of glass reveals following composition (here H2O means water, for example): SiO2 - 62%, AI2O3 -12,5%, CaO - 7,2%, Fe2O3 - 4,6%, MgO - 2,6%, Au - 0,32%, TiO2 - 0,29%, MnO - 0,07%, WO3 - 0,013%. Chemical compounds of S (0.2%) also were present. Melted glass was enriched for 100-1000 times with: Sb, Ba, Ni, W, Fe, Zn, Cu, Pb, Mo, Cr, V, Nb, Cd, Hg, Au, Bi, Zr as compared with surroundings. At 2 km distance from this place another in some way similar unusual place was discovered. Geophysical research in areas reveals the presence short-time intensive increase of temperature, probably looking like a number of concentric rings. Both areas are close to tectonic fault.
These times where the times of political and economical collapse of the USSR. So a little attention was paid to this event.
Here is another event, which also hints on the possible origin of such events. It took place a night before aftershock M=5 of the 27 May, 1976 Lungling earthquake (China). Two Chinese seismologists observed a fireball about 50 metres in diameter 200 meters away. They watched the fireball for almost half an hour. Next morning at the fireball's site they found "an extensive remnant of a sand boil".
At the end, it is interesting to note that some tektite-like objects were found at the epicenter of the 1908 Tunguska explosion. A Russian researcher G. Sal'nikova writes that below fallen trees and in rock cracks black glassy layered particles were discovered among others. Their dimensions were about 1 cm. Here is a composition of one of them. SiO2 - 73.87%; Al2O3 - 12.69%; Fe2O3 - 0.47%; FeO - 4.16%; MgO - 2.18%; CaO - 2.23%; Na2O - 1.38%; K2O - 2.28%; TiO2 - 0.75; MnO - 0.1%. Other chemical elements contained less than 0.1% are (in decreasing order of importance): Ni, Co, Ba, Cu, Be, P, Mo, Ga, Ge, Zn. These are the only findings at the Tunguska epicenter, resembling tektites. Here the author would also recall some local Evenks reports of 'burned (molten) soil and sand' in the epicenter.
Who knows, maybe the initial idea of 'lightning strikes' was closer to the Truth than the modern one?--------------------------------------------------------------
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