In these pages I examine some soil samples / lithologies in which tektites have reportedly been found.
Why am I doing this?
Well, the sculpture of the tektite, as we see it today, is largely due to etching by ground waters and by abrasion due to water transportation (and wind in desert areas). Etching is far from random - it attacks lines of weaknesses in the glass (i.e. cracks) that have formed as the tektite re-entered the Earth's atmosphere. The degree of etching is controlled by the pH of the water, with an acidic environment favouring etching and an alkaline environment apparently favouring preservation. The pH of the groundwater will be largely controlled by the geology of the underlying rocks and the rocks in which the tektites are encased. Additionally, porous and permeable gravels favour contact with water, impermeable rocks may help to preserve tektites.
So, in summary this is what I currently believe to be true:
Tektites in the sea are preserved well due to the alkaline sea water, this is most evident by the preservation of even the smallest micro-tektite. The amazing preservation of Port Campbell australites is probably largely due to the fact that they were originally deposited in marine sediments and only recently exposed on land. Additionally, minute tektites can be found in the Western Australian salt lakes - an alkaline salty environment preserves tektites.
Tektites on land, in carbonate sediments, are preserved well due to the alkaline environment (i.e. hard water). They are less likely to be found, however, as they are less likely to have been sorted and concentrated by water transportation. In fact, I wouldn't even think of looking for tektites in a limestone. A carbonate-rich gravel might represent our best chances of finding numerous well preserved tektites.
Tektites on land, in granitic areas, are likely to be deeply etched. This is because the groundwater will be slightly acidic.
Over time, tektites are reworked into new and younger sediments, probably numerous times since their fall. Transportation sorts tektites and deposits them in gravels with similar sized particles. Gravels are highly porous and permeable, leading to close contact of the tektite with waters - if the waters are acidic the tektite will gradually be etched away, until totally dissolved. It takes a really special environment on land to avoid this reworking into gravels, which inevitably leads to the desruction of the tektite.
I believe numerous studies (some in Czech language) have been done on the gravels in the Czech Republic, which contain the often heavily etched moldavites. I hope to study this more in the future.
In the meantime, please enjoy my data on tektite lithologies.................